Rewrite the world, with several interdependant changes (but several still WIP)

[ldk-java] / genbindings.py

diff --git a/genbindings.py b/genbindings.py
index 5f4edfc71a94489908a46b89e1d40ecfa48d5697..e139af0c1a3b2221ad752a334a6a1603c0bf8440 100755 (executable)
--- a/genbindings.py
+++ b/genbindings.py
@@ -2,34 +2,56 @@
 import sys, re
 
 if len(sys.argv) != 6:
 import sys, re
 
 if len(sys.argv) != 6:

-    print("USAGE: /path/to/lightning.h /path/to/bindings/output.java /path/to/bindings/enums/ /path/to/bindings/output.c debug")
+    print("USAGE: /path/to/lightning.h /path/to/bindings/output.java /path/to/bindings/ /path/to/bindings/output.c debug")

     print("debug should be true or false and indicates whether to track allocations and ensure we don't leak")
     sys.exit(1)
 
     print("debug should be true or false and indicates whether to track allocations and ensure we don't leak")
     sys.exit(1)
 

+hu_struct_file_prefix = """package org.ldk.structs;
+
+import org.ldk.impl.bindings;
+import org.ldk.enums.*;
+import org.ldk.util.*;
+import java.util.Arrays;
+
+@SuppressWarnings("unchecked") // We correctly assign various generic arrays
+"""
+

 class TypeInfo:
 class TypeInfo:

-    def __init__(self, rust_obj, java_ty, java_fn_ty_arg, c_ty, passed_as_ptr, is_ptr, var_name, arr_len):
+    def __init__(self, is_native_primitive, rust_obj, java_ty, java_fn_ty_arg, java_hu_ty, c_ty, passed_as_ptr, is_ptr, var_name, arr_len, arr_access, subty=None):
+        self.is_native_primitive = is_native_primitive

         self.rust_obj = rust_obj
         self.java_ty = java_ty
         self.rust_obj = rust_obj
         self.java_ty = java_ty

+        self.java_hu_ty = java_hu_ty

         self.java_fn_ty_arg = java_fn_ty_arg
         self.c_ty = c_ty
         self.passed_as_ptr = passed_as_ptr
         self.is_ptr = is_ptr
         self.var_name = var_name
         self.arr_len = arr_len
         self.java_fn_ty_arg = java_fn_ty_arg
         self.c_ty = c_ty
         self.passed_as_ptr = passed_as_ptr
         self.is_ptr = is_ptr
         self.var_name = var_name
         self.arr_len = arr_len

+        self.arr_access = arr_access
+        self.subty = subty
+        self.pass_by_ref = is_ptr

 
 class ConvInfo:
 
 class ConvInfo:

-    def __init__(self, ty_info, arg_name, arg_conv, arg_conv_name, ret_conv, ret_conv_name):
+    def __init__(self, ty_info, arg_name, arg_conv, arg_conv_name, arg_conv_cleanup, ret_conv, ret_conv_name, to_hu_conv, to_hu_conv_name, from_hu_conv):

         assert(ty_info.c_ty is not None)
         assert(ty_info.java_ty is not None)
         assert(arg_name is not None)
         assert(ty_info.c_ty is not None)
         assert(ty_info.java_ty is not None)
         assert(arg_name is not None)

+        self.passed_as_ptr = ty_info.passed_as_ptr
+        self.rust_obj = ty_info.rust_obj

         self.c_ty = ty_info.c_ty
         self.java_ty = ty_info.java_ty
         self.c_ty = ty_info.c_ty
         self.java_ty = ty_info.java_ty

+        self.java_hu_ty = ty_info.java_hu_ty

         self.java_fn_ty_arg = ty_info.java_fn_ty_arg
         self.arg_name = arg_name
         self.arg_conv = arg_conv
         self.arg_conv_name = arg_conv_name
         self.java_fn_ty_arg = ty_info.java_fn_ty_arg
         self.arg_name = arg_name
         self.arg_conv = arg_conv
         self.arg_conv_name = arg_conv_name

+        self.arg_conv_cleanup = arg_conv_cleanup

         self.ret_conv = ret_conv
         self.ret_conv_name = ret_conv_name
         self.ret_conv = ret_conv
         self.ret_conv_name = ret_conv_name

+        self.to_hu_conv = to_hu_conv
+        self.to_hu_conv_name = to_hu_conv_name
+        self.from_hu_conv = from_hu_conv

 
     def print_ty(self):
         out_c.write(self.c_ty)
 
     def print_ty(self):
         out_c.write(self.c_ty)


@@ -43,138 +65,312 @@ class ConvInfo:
             out_java.write(" arg")
             out_c.write(" arg")
 
             out_java.write(" arg")
             out_c.write(" arg")
 

-with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.argv[4], "w") as out_c:
-    opaque_structs = set()
-    trait_structs = set()
-    unitary_enums = set()
-
-    def camel_to_snake(s):
-        # Convert camel case to snake case, in a way that appears to match cbindgen
-        con = "_"
-        ret = ""
-        lastchar = ""
-        lastund = False
-        for char in s:
-            if lastchar.isupper():
-                if not char.isupper() and not lastund:
-                    ret = ret + "_"
-                    lastund = True
-                else:
-                    lastund = False
-                ret = ret + lastchar.lower()
+def camel_to_snake(s):
+    # Convert camel case to snake case, in a way that appears to match cbindgen
+    con = "_"
+    ret = ""
+    lastchar = ""
+    lastund = False
+    for char in s:
+        if lastchar.isupper():
+            if not char.isupper() and not lastund:
+                ret = ret + "_"
+                lastund = True

             else:
             else:

-                ret = ret + lastchar
-                if char.isupper() and not lastund:
-                    ret = ret + "_"
-                    lastund = True
-                else:
-                    lastund = False
-            lastchar = char
-            if char.isnumeric():
+                lastund = False
+            ret = ret + lastchar.lower()
+        else:
+            ret = ret + lastchar
+            if char.isupper() and not lastund:
+                ret = ret + "_"

                 lastund = True
                 lastund = True

-        return (ret + lastchar.lower()).strip("_")
-
-    var_is_arr_regex = re.compile("\(\*([A-za-z0-9_]*)\)\[([0-9]*)\]")
-    var_ty_regex = re.compile("([A-za-z_0-9]*)(.*)")
-    def java_c_types(fn_arg, ret_arr_len):
-        fn_arg = fn_arg.strip()
-        if fn_arg.startswith("MUST_USE_RES "):
-            fn_arg = fn_arg[13:]
-        is_const = False
-        if fn_arg.startswith("const "):
-            fn_arg = fn_arg[6:]
-            is_const = True
-
-        is_ptr = False
-        take_by_ptr = False
-        rust_obj = None
-        if fn_arg.startswith("LDKThirtyTwoBytes"):
-            fn_arg = "uint8_t (*" + fn_arg[18:] + ")[32]"
+            else:
+                lastund = False
+        lastchar = char
+        if char.isnumeric():
+            lastund = True
+    return (ret + lastchar.lower()).strip("_")
+
+unitary_enums = set()
+complex_enums = set()
+opaque_structs = set()
+trait_structs = set()
+tuple_types = {}
+
+var_is_arr_regex = re.compile("\(\*([A-za-z0-9_]*)\)\[([a-z0-9]*)\]")
+var_ty_regex = re.compile("([A-za-z_0-9]*)(.*)")
+java_c_types_none_allowed = True # Unset when we do the real pass that populates the above sets
+def java_c_types(fn_arg, ret_arr_len):
+    fn_arg = fn_arg.strip()
+    if fn_arg.startswith("MUST_USE_RES "):
+        fn_arg = fn_arg[13:]
+    is_const = False
+    if fn_arg.startswith("const "):
+        fn_arg = fn_arg[6:]
+        is_const = True
+
+    is_ptr = False
+    take_by_ptr = False
+    rust_obj = None
+    arr_access = None
+    java_hu_ty = None
+    if fn_arg.startswith("LDKThirtyTwoBytes"):
+        fn_arg = "uint8_t (*" + fn_arg[18:] + ")[32]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKThirtyTwoBytes"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKPublicKey"):
+        fn_arg = "uint8_t (*" + fn_arg[13:] + ")[33]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKPublicKey"
+        arr_access = "compressed_form"
+    elif fn_arg.startswith("LDKSecretKey"):
+        fn_arg = "uint8_t (*" + fn_arg[13:] + ")[32]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKSecretKey"
+        arr_access = "bytes"
+    elif fn_arg.startswith("LDKSignature"):
+        fn_arg = "uint8_t (*" + fn_arg[13:] + ")[64]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKSignature"
+        arr_access = "compact_form"
+    elif fn_arg.startswith("LDKThreeBytes"):
+        fn_arg = "uint8_t (*" + fn_arg[14:] + ")[3]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKThreeBytes"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKFourBytes"):
+        fn_arg = "uint8_t (*" + fn_arg[13:] + ")[4]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKFourBytes"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKSixteenBytes"):
+        fn_arg = "uint8_t (*" + fn_arg[16:] + ")[16]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKSixteenBytes"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKTenBytes"):
+        fn_arg = "uint8_t (*" + fn_arg[12:] + ")[10]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKTenBytes"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKu8slice"):
+        fn_arg = "uint8_t (*" + fn_arg[11:] + ")[datalen]"
+        assert var_is_arr_regex.match(fn_arg[8:])
+        rust_obj = "LDKu8slice"
+        arr_access = "data"
+    elif fn_arg.startswith("LDKCVecTempl_u8") or fn_arg.startswith("LDKCVec_u8Z"):
+        if fn_arg.startswith("LDKCVecTempl_u8"):
+            fn_arg = "uint8_t (*" + fn_arg[16:] + ")[datalen]"
+            rust_obj = "LDKCVecTempl_u8"

             assert var_is_arr_regex.match(fn_arg[8:])
             assert var_is_arr_regex.match(fn_arg[8:])

-            rust_obj = "LDKThirtyTwoBytes"
-
-        if fn_arg.startswith("void"):
-            java_ty = "void"
-            c_ty = "void"
-            fn_ty_arg = "V"
-            fn_arg = fn_arg[4:].strip()
-        elif fn_arg.startswith("bool"):
-            java_ty = "boolean"
-            c_ty = "jboolean"
-            fn_ty_arg = "Z"
-            fn_arg = fn_arg[4:].strip()
-        elif fn_arg.startswith("uint8_t"):
-            java_ty = "byte"
-            c_ty = "jbyte"
-            fn_ty_arg = "B"
-            fn_arg = fn_arg[7:].strip()
-        elif fn_arg.startswith("uint16_t"):
-            java_ty = "short"
-            c_ty = "jshort"
-            fn_ty_arg = "S"
-            fn_arg = fn_arg[8:].strip()
-        elif fn_arg.startswith("uint32_t"):
-            java_ty = "int"
-            c_ty = "jint"
-            fn_ty_arg = "I"
+        else:
+            fn_arg = "uint8_t (*" + fn_arg[12:] + ")[datalen]"
+            rust_obj = "LDKCVec_u8Z"
+            assert var_is_arr_regex.match(fn_arg[8:])
+        arr_access = "data"
+    elif fn_arg.startswith("LDKCVecTempl_") or fn_arg.startswith("LDKCVec_"):
+        is_ptr = False
+        if "*" in fn_arg:
+            fn_arg = fn_arg.replace("*", "")
+            is_ptr = True
+
+        if fn_arg.startswith("LDKCVec_"):
+            tyn = fn_arg[8:].split(" ")
+            assert tyn[0].endswith("Z")
+            if tyn[0] == "u64Z":
+                new_arg = "uint64_t"
+            else:
+                new_arg = "LDK" + tyn[0][:-1]
+            for a in tyn[1:]:
+                new_arg = new_arg + " " + a
+            res = java_c_types(new_arg, ret_arr_len)
+        else:
+            res = java_c_types("LDK" + fn_arg[13:], ret_arr_len)
+        if res is None:
+            assert java_c_types_none_allowed
+            return None
+        if is_ptr:
+            res.pass_by_ref = True
+        if res.is_native_primitive or res.passed_as_ptr:
+            return TypeInfo(rust_obj=fn_arg.split(" ")[0], java_ty=res.java_ty + "[]", java_hu_ty=res.java_hu_ty + "[]",
+                java_fn_ty_arg="[" + res.java_fn_ty_arg, c_ty=res.c_ty + "Array", passed_as_ptr=False, is_ptr=is_ptr,
+                var_name=res.var_name, arr_len="datalen", arr_access="data", subty=res, is_native_primitive=False)
+        else:
+            return TypeInfo(rust_obj=fn_arg.split(" ")[0], java_ty=res.java_ty + "[]", java_hu_ty=res.java_hu_ty + "[]",
+                java_fn_ty_arg="[" + res.java_fn_ty_arg, c_ty="jobjectArray", passed_as_ptr=False, is_ptr=is_ptr,
+                var_name=res.var_name, arr_len="datalen", arr_access="data", subty=res, is_native_primitive=False)
+
+    is_primitive = False
+    arr_len = None
+    if fn_arg.startswith("void"):
+        java_ty = "void"
+        c_ty = "void"
+        fn_ty_arg = "V"
+        fn_arg = fn_arg[4:].strip()
+        is_primitive = True
+    elif fn_arg.startswith("bool"):
+        java_ty = "boolean"
+        c_ty = "jboolean"
+        fn_ty_arg = "Z"
+        fn_arg = fn_arg[4:].strip()
+        is_primitive = True
+    elif fn_arg.startswith("uint8_t"):
+        java_ty = "byte"
+        c_ty = "jbyte"
+        fn_ty_arg = "B"
+        fn_arg = fn_arg[7:].strip()
+        is_primitive = True
+    elif fn_arg.startswith("uint16_t"):
+        java_ty = "short"
+        c_ty = "jshort"
+        fn_ty_arg = "S"
+        fn_arg = fn_arg[8:].strip()
+        is_primitive = True
+    elif fn_arg.startswith("uint32_t"):
+        java_ty = "int"
+        c_ty = "jint"
+        fn_ty_arg = "I"
+        fn_arg = fn_arg[8:].strip()
+        is_primitive = True
+    elif fn_arg.startswith("uint64_t") or fn_arg.startswith("uintptr_t"):
+        java_ty = "long"
+        c_ty = "jlong"
+        fn_ty_arg = "J"
+        if fn_arg.startswith("uint64_t"):

             fn_arg = fn_arg[8:].strip()
             fn_arg = fn_arg[8:].strip()

-        elif fn_arg.startswith("uint64_t") or fn_arg.startswith("uintptr_t"):
+        else:
+            fn_arg = fn_arg[9:].strip()
+        is_primitive = True
+    elif is_const and fn_arg.startswith("char *"):
+        java_ty = "String"
+        c_ty = "const char*"
+        fn_ty_arg = "Ljava/lang/String;"
+        fn_arg = fn_arg[6:].strip()
+    elif fn_arg.startswith("LDKStr"):
+        java_ty = "String"
+        c_ty = "jstring"
+        fn_ty_arg = "Ljava/lang/String;"
+        fn_arg = fn_arg[6:].strip()
+        arr_access = "chars"
+        arr_len = "len"
+    else:
+        ma = var_ty_regex.match(fn_arg)
+        if ma.group(1).strip() in unitary_enums:
+            java_ty = ma.group(1).strip()
+            c_ty = "jclass"
+            fn_ty_arg = "Lorg/ldk/enums/" + ma.group(1).strip() + ";"
+            fn_arg = ma.group(2).strip()
+            rust_obj = ma.group(1).strip()
+            take_by_ptr = True
+        elif ma.group(1).strip().startswith("LDKC2Tuple"):

             java_ty = "long"
             java_ty = "long"

+            java_hu_ty = "TwoTuple<"
+            if not ma.group(1).strip() in tuple_types:
+                assert java_c_types_none_allowed
+                return None
+            for idx, ty_info in enumerate(tuple_types[ma.group(1).strip()][0]):
+                if idx != 0:
+                    java_hu_ty = java_hu_ty + ", "
+                if ty_info.is_native_primitive:
+                    java_hu_ty = java_hu_ty + ty_info.java_hu_ty.title() # If we're a primitive, capitalize the first letter
+                else:
+                    java_hu_ty = java_hu_ty + ty_info.java_hu_ty
+            java_hu_ty = java_hu_ty + ">"

             c_ty = "jlong"
             fn_ty_arg = "J"
             c_ty = "jlong"
             fn_ty_arg = "J"

-            if fn_arg.startswith("uint64_t"):
-                fn_arg = fn_arg[8:].strip()
-            else:
-                fn_arg = fn_arg[9:].strip()
-        elif is_const and fn_arg.startswith("char *"):
-            java_ty = "String"
-            c_ty = "const char*"
-            fn_ty_arg = "Ljava/lang/String;"
-            fn_arg = fn_arg[6:].strip()
-        else:
-            ma = var_ty_regex.match(fn_arg)
-            if ma.group(1).strip() in unitary_enums:
-                java_ty = ma.group(1).strip()
-                c_ty = "jclass"
-                fn_ty_arg = "Lorg/ldk/enums/" + ma.group(1).strip() + ";"
-                fn_arg = ma.group(2).strip()
-                rust_obj = ma.group(1).strip()
-                take_by_ptr = True
-            else:
-                java_ty = "long"
-                c_ty = "jlong"
-                fn_ty_arg = "J"
-                fn_arg = ma.group(2).strip()
-                rust_obj = ma.group(1).strip()
-                take_by_ptr = True
-
-        if fn_arg.startswith(" *") or fn_arg.startswith("*"):
-            fn_arg = fn_arg.replace("*", "").strip()
-            is_ptr = True
+            fn_arg = ma.group(2).strip()
+            rust_obj = ma.group(1).strip()
+            take_by_ptr = True
+        elif ma.group(1).strip().startswith("LDKC3Tuple"):
+            java_ty = "long"
+            java_hu_ty = "ThreeTuple<"
+            if not ma.group(1).strip() in tuple_types:
+                assert java_c_types_none_allowed
+                return None
+            for idx, ty_info in enumerate(tuple_types[ma.group(1).strip()][0]):
+                if idx != 0:
+                    java_hu_ty = java_hu_ty + ", "
+                if ty_info.is_native_primitive:
+                    java_hu_ty = java_hu_ty + ty_info.java_hu_ty.title() # If we're a primitive, capitalize the first letter
+                else:
+                    java_hu_ty = java_hu_ty + ty_info.java_hu_ty
+            java_hu_ty = java_hu_ty + ">"

             c_ty = "jlong"
             c_ty = "jlong"

+            fn_ty_arg = "J"
+            fn_arg = ma.group(2).strip()
+            rust_obj = ma.group(1).strip()
+            take_by_ptr = True
+        else:

             java_ty = "long"
             java_ty = "long"

+            java_hu_ty = ma.group(1).strip().replace("LDK", "")
+            c_ty = "jlong"

             fn_ty_arg = "J"
             fn_ty_arg = "J"

+            fn_arg = ma.group(2).strip()
+            rust_obj = ma.group(1).strip()
+            take_by_ptr = True
+
+    if fn_arg.startswith(" *") or fn_arg.startswith("*"):
+        fn_arg = fn_arg.replace("*", "").strip()
+        is_ptr = True
+        c_ty = "jlong"
+        java_ty = "long"
+        fn_ty_arg = "J"
+        is_primitive = False
+
+    var_is_arr = var_is_arr_regex.match(fn_arg)
+    if var_is_arr is not None or ret_arr_len is not None:
+        assert(not take_by_ptr)
+        assert(not is_ptr)
+        java_ty = java_ty + "[]"
+        c_ty = c_ty + "Array"
+        if var_is_arr is not None:
+            if var_is_arr.group(1) == "":
+                return TypeInfo(rust_obj=rust_obj, java_ty=java_ty, java_hu_ty=java_ty, java_fn_ty_arg="[" + fn_ty_arg, c_ty=c_ty,
+                    passed_as_ptr=False, is_ptr=False, var_name="arg", arr_len=var_is_arr.group(2), arr_access=arr_access, is_native_primitive=False)
+            return TypeInfo(rust_obj=rust_obj, java_ty=java_ty, java_hu_ty=java_ty, java_fn_ty_arg="[" + fn_ty_arg, c_ty=c_ty,
+                passed_as_ptr=False, is_ptr=False, var_name=var_is_arr.group(1), arr_len=var_is_arr.group(2), arr_access=arr_access, is_native_primitive=False)
+
+    if java_hu_ty is None:
+        java_hu_ty = java_ty
+    return TypeInfo(rust_obj=rust_obj, java_ty=java_ty, java_hu_ty=java_hu_ty, java_fn_ty_arg=fn_ty_arg, c_ty=c_ty, passed_as_ptr=is_ptr or take_by_ptr,
+        is_ptr=is_ptr, var_name=fn_arg, arr_len=arr_len, arr_access=arr_access, is_native_primitive=is_primitive)
+
+fn_ptr_regex = re.compile("^extern const ([A-Za-z_0-9\* ]*) \(\*(.*)\)\((.*)\);$")
+fn_ret_arr_regex = re.compile("(.*) \(\*(.*)\((.*)\)\)\[([0-9]*)\];$")
+reg_fn_regex = re.compile("([A-Za-z_0-9\* ]* \*?)([a-zA-Z_0-9]*)\((.*)\);$")
+clone_fns = set()
+constructor_fns = {}
+with open(sys.argv[1]) as in_h:
+    for line in in_h:
+        reg_fn = reg_fn_regex.match(line)
+        if reg_fn is not None:
+            if reg_fn.group(2).endswith("_clone"):
+                clone_fns.add(reg_fn.group(2))
+            else:
+                rty = java_c_types(reg_fn.group(1), None)
+                if rty is not None and rty.rust_obj is not None and reg_fn.group(2) == rty.java_hu_ty + "_new":
+                    constructor_fns[rty.rust_obj] = reg_fn.group(3)
+            continue
+        arr_fn = fn_ret_arr_regex.match(line)
+        if arr_fn is not None:
+            if arr_fn.group(2).endswith("_clone"):
+                clone_fns.add(arr_fn.group(2))
+            # No object constructors return arrays, as then they wouldn't be an object constructor
+            continue
+java_c_types_none_allowed = False # C structs created by cbindgen are declared in dependency order

 
 

-        var_is_arr = var_is_arr_regex.match(fn_arg)
-        if var_is_arr is not None or ret_arr_len is not None:
-            assert(not take_by_ptr)
-            assert(not is_ptr)
-            java_ty = java_ty + "[]"
-            c_ty = c_ty + "Array"
-            if var_is_arr is not None:
-                return TypeInfo(rust_obj=rust_obj, java_ty=java_ty, java_fn_ty_arg="[" + fn_ty_arg, c_ty=c_ty,
-                    passed_as_ptr=False, is_ptr=False, var_name=var_is_arr.group(1), arr_len=var_is_arr.group(2))
-        return TypeInfo(rust_obj=rust_obj, java_ty=java_ty, java_fn_ty_arg=fn_ty_arg, c_ty=c_ty, passed_as_ptr=is_ptr or take_by_ptr,
-            is_ptr=is_ptr, var_name=fn_arg, arr_len=None)
-
+with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.argv[4], "w") as out_c:

     def map_type(fn_arg, print_void, ret_arr_len, is_free):
         ty_info = java_c_types(fn_arg, ret_arr_len)
     def map_type(fn_arg, print_void, ret_arr_len, is_free):
         ty_info = java_c_types(fn_arg, ret_arr_len)

+        return map_type_with_info(ty_info, print_void, ret_arr_len, is_free)

 
 

+    def map_type_with_info(ty_info, print_void, ret_arr_len, is_free):

         if ty_info.c_ty == "void":
             if not print_void:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
         if ty_info.c_ty == "void":
             if not print_void:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                    arg_conv = None, arg_conv_name = None, ret_conv = None, ret_conv_name = None)
-
+                    arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None, to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

         if ty_info.c_ty.endswith("Array"):
             arr_len = ty_info.arr_len
             if arr_len is not None:
         if ty_info.c_ty.endswith("Array"):
             arr_len = ty_info.arr_len
             if arr_len is not None:


@@ -182,20 +378,130 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
             else:
                 arr_name = "ret"
                 arr_len = ret_arr_len
             else:
                 arr_name = "ret"
                 arr_len = ret_arr_len

-            assert(ty_info.c_ty == "jbyteArray")
-            if ty_info.rust_obj is not None:
-                arg_conv = ty_info.rust_obj + " " + arr_name + "_ref;\n" + "(*_env)->GetByteArrayRegion (_env, " + arr_name + ", 0, " + arr_len + ", " + arr_name + "_ref.data);"
-                arr_access = ("", ".data")
+            if ty_info.c_ty == "jbyteArray":
+                ret_conv = ("jbyteArray " + arr_name + "_arr = (*_env)->NewByteArray(_env, " + arr_len + ");\n" + "(*_env)->SetByteArrayRegion(_env, " + arr_name + "_arr, 0, " + arr_len + ", ", "")
+                arg_conv_cleanup = None
+                if not arr_len.isdigit():
+                    arg_conv = ty_info.rust_obj + " " + arr_name + "_ref;\n"
+                    arg_conv = arg_conv + arr_name + "_ref." + ty_info.arr_access + " = (*_env)->GetByteArrayElements (_env, " + arr_name + ", NULL);\n"
+                    arg_conv = arg_conv + arr_name + "_ref." + arr_len + " = (*_env)->GetArrayLength (_env, " + arr_name + ");"
+                    arg_conv_cleanup = "(*_env)->ReleaseByteArrayElements(_env, " + arr_name + ", (int8_t*)" + arr_name + "_ref." + ty_info.arr_access + ", 0);"
+                    ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
+                    ret_conv = (ret_conv[0], ";\njbyteArray " + arr_name + "_arr = (*_env)->NewByteArray(_env, " + arr_name + "_var." + arr_len + ");\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "(*_env)->SetByteArrayRegion(_env, " + arr_name + "_arr, 0, " + arr_name + "_var." + arr_len + ", " + arr_name + "_var." + ty_info.arr_access + ");")
+                elif ty_info.rust_obj is not None:
+                    arg_conv = ty_info.rust_obj + " " + arr_name + "_ref;\n"
+                    arg_conv = arg_conv + "CHECK((*_env)->GetArrayLength (_env, " + arr_name + ") == " + arr_len + ");\n"
+                    arg_conv = arg_conv + "(*_env)->GetByteArrayRegion (_env, " + arr_name + ", 0, " + arr_len + ", " + arr_name + "_ref." + ty_info.arr_access + ");"
+                    ret_conv = (ret_conv[0], "." + ty_info.arr_access + ");")
+                else:
+                    arg_conv = "unsigned char " + arr_name + "_arr[" + arr_len + "];\n"
+                    arg_conv = arg_conv + "CHECK((*_env)->GetArrayLength (_env, " + arr_name + ") == " + arr_len + ");\n"
+                    arg_conv = arg_conv + "(*_env)->GetByteArrayRegion (_env, " + arr_name + ", 0, " + arr_len + ", " + arr_name + "_arr);\n" + "unsigned char (*" + arr_name + "_ref)[" + arr_len + "] = &" + arr_name + "_arr;"
+                    ret_conv = (ret_conv[0] + "*", ");")
+                return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                    arg_conv = arg_conv, arg_conv_name = arr_name + "_ref", arg_conv_cleanup = arg_conv_cleanup,
+                    ret_conv = ret_conv, ret_conv_name = arr_name + "_arr", to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

             else:
             else:

-                arg_conv = "unsigned char " + arr_name + "_arr[" + arr_len + "];\n" + "(*_env)->GetByteArrayRegion (_env, " + arr_name + ", 0, " + arr_len + ", " + arr_name + "_arr);\n" + "unsigned char (*" + arr_name + "_ref)[" + arr_len + "] = &" + arr_name + "_arr;"
-                arr_access = ("*", "")
-            return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
-                arg_conv = arg_conv,
-                arg_conv_name = arr_name + "_ref",
-                ret_conv = ("jbyteArray " + arr_name + "_arr = (*_env)->NewByteArray(_env, " + arr_len + ");\n" +
-                    "(*_env)->SetByteArrayRegion(_env, " + arr_name + "_arr, 0, " + arr_len + ", " + arr_access[0],
-                    arr_access[1] + ");"),
-                ret_conv_name = arr_name + "_arr")
+                assert not arr_len.isdigit() # not implemented
+                assert ty_info.java_ty[len(ty_info.java_ty) - 2:] == "[]"
+                conv_name = "arr_conv_" + str(len(ty_info.java_hu_ty))
+                idxc = chr(ord('a') + (len(ty_info.java_hu_ty) % 26))
+                ty_info.subty.var_name = conv_name
+                subty = map_type_with_info(ty_info.subty, False, None, is_free)
+                if arr_name == "":
+                    arr_name = "arg"
+                arg_conv = ty_info.rust_obj + " " + arr_name + "_constr;\n"
+                arg_conv = arg_conv + arr_name + "_constr." + arr_len + " = (*_env)->GetArrayLength (_env, " + arr_name + ");\n"
+                arg_conv = arg_conv + "if (" + arr_name + "_constr." + arr_len + " > 0)\n"
+                if subty.rust_obj is None:
+                    szof = subty.c_ty
+                else:
+                    szof = subty.rust_obj
+                arg_conv = arg_conv + "\t" + arr_name + "_constr." + ty_info.arr_access + " = MALLOC(" + arr_name + "_constr." + arr_len + " * sizeof(" + szof + "), \"" + ty_info.rust_obj + " Elements\");\n"
+                arg_conv = arg_conv + "else\n"
+                arg_conv = arg_conv + "\t" + arr_name + "_constr." + ty_info.arr_access + " = NULL;\n"
+                if not ty_info.java_ty[:len(ty_info.java_ty) - 2].endswith("[]"):
+                    arg_conv = arg_conv + ty_info.java_ty.strip("[]") + "* " + arr_name + "_vals = (*_env)->Get" + ty_info.subty.java_ty.title() + "ArrayElements (_env, " + arr_name + ", NULL);\n"
+                arg_conv = arg_conv + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_constr." + arr_len + "; " + idxc + "++) {\n"
+                if not ty_info.java_ty[:len(ty_info.java_ty) - 2].endswith("[]"):
+                    arg_conv = arg_conv + "\t" + ty_info.java_ty.strip("[]") + " " + conv_name + " = " + arr_name + "_vals[" + idxc + "];"
+                    if subty.arg_conv is not None:
+                        arg_conv = arg_conv + "\n\t" + subty.arg_conv.replace("\n", "\n\t")
+                else:
+                    arg_conv = arg_conv + "\tjobject " + conv_name + " = (*_env)->GetObjectArrayElement(_env, " + arr_name + ", " + idxc + ");\n"
+                    arg_conv = arg_conv + "\t" + subty.arg_conv.replace("\n", "\n\t")
+                arg_conv = arg_conv + "\n\t" + arr_name + "_constr." + ty_info.arr_access + "[" + idxc + "] = " + subty.arg_conv_name + ";\n}"
+                if not ty_info.java_ty[:len(ty_info.java_ty) - 2].endswith("[]"):
+                    arg_conv = arg_conv + "\n(*_env)->Release" + ty_info.java_ty.strip("[]").title() + "ArrayElements (_env, " + arr_name + ", " + arr_name + "_vals, 0);"
+                if ty_info.is_ptr:
+                    arg_conv_name = "&" + arr_name + "_constr"
+                else:
+                    arg_conv_name = arr_name + "_constr"
+                arg_conv_cleanup = None
+                if ty_info.is_ptr:
+                    arg_conv_cleanup = "FREE(" + arr_name + "_constr." + ty_info.arr_access + ");"
+
+                if arr_name == "arg":
+                    arr_name = "ret"
+                ret_conv = (ty_info.rust_obj + " " + arr_name + "_var = ", "")
+                if subty.ret_conv is None:
+                    ret_conv = ("DUMMY", "DUMMY")
+                elif not ty_info.java_ty[:len(ty_info.java_ty) - 2].endswith("[]"):
+                    ret_conv = (ret_conv[0], ";\n" + ty_info.c_ty + " " + arr_name + "_arr = (*_env)->New" + ty_info.java_ty.strip("[]").title() + "Array(_env, " + arr_name + "_var." + arr_len + ");\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + subty.c_ty + " *" + arr_name + "_arr_ptr = (*_env)->GetPrimitiveArrayCritical(_env, " + arr_name + "_arr, NULL);\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_var." + arr_len + "; " + idxc + "++) {\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "\t" + subty.ret_conv[0].replace("\n", "\n\t"))
+                    ret_conv = (ret_conv[0], ret_conv[1] + arr_name + "_var." + ty_info.arr_access + "[" + idxc + "]" + subty.ret_conv[1].replace("\n", "\n\t"))
+                    ret_conv = (ret_conv[0], ret_conv[1] + "\n\t" + arr_name + "_arr_ptr[" + idxc + "] = " + subty.ret_conv_name + ";\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "}\n(*_env)->ReleasePrimitiveArrayCritical(_env, " + arr_name + "_arr, " + arr_name + "_arr_ptr, 0);")
+                else:
+                    ret_conv = (ret_conv[0], ";\n" + ty_info.c_ty + " " + arr_name + "_arr = (*_env)->NewObjectArray(_env, " + arr_name + "_var." + arr_len + ", NULL, NULL);\n") # XXX: second arg needs to be a clazz!
+                    ret_conv = (ret_conv[0], ret_conv[1] + "for (size_t " + idxc + " = 0; " + idxc + " < " + arr_name + "_var." + arr_len + "; " + idxc + "++) {\n")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "\t" + subty.ret_conv[0].replace("\n", "\n\t"))
+                    ret_conv = (ret_conv[0], ret_conv[1] + arr_name + "_var." + ty_info.arr_access + "[" + idxc + "]" + subty.ret_conv[1].replace("\n", "\n\t"))
+                    ret_conv = (ret_conv[0], ret_conv[1] + "\n\t(*_env)->SetObjectArrayElement(_env, " + arr_name + "_arr, " + idxc + ", " + subty.ret_conv_name + ");")
+                    ret_conv = (ret_conv[0], ret_conv[1] + "}")
+                if subty.rust_obj is not None and subty.rust_obj in opaque_structs:
+                    ret_conv = (ret_conv[0], ret_conv[1] + "\nFREE(" + arr_name + "_var.data);")
+
+                to_hu_conv = None
+                to_hu_conv_name = None
+                if subty.to_hu_conv is not None:
+                    to_hu_conv = ty_info.java_hu_ty + " " + conv_name + "_arr = new " + ty_info.subty.java_hu_ty.split("<")[0] + "[" + arr_name + ".length];\n"
+                    to_hu_conv = to_hu_conv + "for (int " + idxc + " = 0; " + idxc + " < " + arr_name + ".length; " + idxc + "++) {\n"
+                    to_hu_conv = to_hu_conv + "\t" + subty.java_ty + " " + conv_name + " = " + arr_name + "[" + idxc + "];\n"
+                    to_hu_conv = to_hu_conv + "\t" + subty.to_hu_conv.replace("\n", "\n\t") + "\n"
+                    to_hu_conv = to_hu_conv + "\t" + conv_name + "_arr[" + idxc + "] = " + subty.to_hu_conv_name + ";\n}"
+                    to_hu_conv_name = conv_name + "_arr"
+                from_hu_conv = None
+                if subty.from_hu_conv is not None:
+                    if subty.java_ty == "long" and subty.java_hu_ty != "long":
+                        from_hu_conv = ("Arrays.stream(" + arr_name + ").mapToLong(" + conv_name + " -> " + subty.from_hu_conv[0] + ").toArray()", "/* TODO 2 " + subty.java_hu_ty + "  */")
+                    elif subty.java_ty == "long":
+                        from_hu_conv = ("Arrays.stream(" + arr_name + ").map(" + conv_name + " -> " + subty.from_hu_conv[0] + ").toArray()", "/* TODO 2 " + subty.java_hu_ty + "  */")
+                    else:
+                        from_hu_conv = ("(" + ty_info.java_ty + ")Arrays.stream(" + arr_name + ").map(" + conv_name + " -> " + subty.from_hu_conv[0] + ").toArray()", "/* TODO 2 " + subty.java_hu_ty + "  */")
+
+                return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                    arg_conv = arg_conv, arg_conv_name = arg_conv_name, arg_conv_cleanup = arg_conv_cleanup,
+                    ret_conv = ret_conv, ret_conv_name = arr_name + "_arr", to_hu_conv = to_hu_conv, to_hu_conv_name = to_hu_conv_name, from_hu_conv = from_hu_conv)
+        elif ty_info.java_ty == "String":
+            if ty_info.arr_access is None:
+                return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                    arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                    ret_conv = ("jstring " + ty_info.var_name + "_conv = (*_env)->NewStringUTF(_env, ", ");"), ret_conv_name = ty_info.var_name + "_conv",
+                    to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)
+            else:
+                return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                    arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                    ret_conv = ("LDKStr " + ty_info.var_name + "_str = ",
+                        ";\nchar* " + ty_info.var_name + "_buf = MALLOC(" + ty_info.var_name + "_str." + ty_info.arr_len + " + 1, \"str conv buf\");\n" +
+                        "memcpy(" + ty_info.var_name + "_buf, " + ty_info.var_name + "_str." + ty_info.arr_access + ", " + ty_info.var_name + "_str." + ty_info.arr_len + ");\n" +
+                        ty_info.var_name + "_buf[" + ty_info.var_name + "_str." + ty_info.arr_len + "] = 0;\n" +
+                        "jstring " + ty_info.var_name + "_conv = (*_env)->NewStringUTF(_env, " + ty_info.var_name + "_str." + ty_info.arr_access + ");\n" +
+                        "FREE(" + ty_info.var_name + "_buf);"),
+                    ret_conv_name = ty_info.var_name + "_conv", to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

         elif ty_info.var_name != "":
             # If we have a parameter name, print it (noting that it may indicate its a pointer)
             if ty_info.rust_obj is not None:
         elif ty_info.var_name != "":
             # If we have a parameter name, print it (noting that it may indicate its a pointer)
             if ty_info.rust_obj is not None:


@@ -203,16 +509,24 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
                 opaque_arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv;\n"
                 opaque_arg_conv = opaque_arg_conv + ty_info.var_name + "_conv.inner = (void*)(" + ty_info.var_name + " & (~1));\n"
                 opaque_arg_conv = opaque_arg_conv + ty_info.var_name + "_conv.is_owned = (" + ty_info.var_name + " & 1) || (" + ty_info.var_name + " == 0);"
                 opaque_arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv;\n"
                 opaque_arg_conv = opaque_arg_conv + ty_info.var_name + "_conv.inner = (void*)(" + ty_info.var_name + " & (~1));\n"
                 opaque_arg_conv = opaque_arg_conv + ty_info.var_name + "_conv.is_owned = (" + ty_info.var_name + " & 1) || (" + ty_info.var_name + " == 0);"

+                if not ty_info.is_ptr and not is_free and not ty_info.pass_by_ref:
+                    if (ty_info.java_hu_ty + "_clone") in clone_fns:
+                        # TODO: This is a bit too naive, even with the checks above, we really need to know if rust wants a ref or not, not just if its pass as a ptr.
+                        opaque_arg_conv = opaque_arg_conv + "\nif (" + ty_info.var_name + "_conv.inner != NULL)\n"
+                        opaque_arg_conv = opaque_arg_conv + "\t" + ty_info.var_name + "_conv = " + ty_info.java_hu_ty + "_clone(&" + ty_info.var_name + "_conv);"
+                    elif ty_info.passed_as_ptr:
+                        opaque_arg_conv = opaque_arg_conv + "\n// Warning: we may need a move here but can't clone!"

                 if not ty_info.is_ptr:
                     if ty_info.rust_obj in unitary_enums:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                             arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = " + ty_info.rust_obj + "_from_java(_env, " + ty_info.var_name + ");",
                             arg_conv_name = ty_info.var_name + "_conv",
                 if not ty_info.is_ptr:
                     if ty_info.rust_obj in unitary_enums:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                             arg_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = " + ty_info.rust_obj + "_from_java(_env, " + ty_info.var_name + ");",
                             arg_conv_name = ty_info.var_name + "_conv",

+                            arg_conv_cleanup = None,

                             ret_conv = ("jclass " + ty_info.var_name + "_conv = " + ty_info.rust_obj + "_to_java(_env, ", ");"),
                             ret_conv = ("jclass " + ty_info.var_name + "_conv = " + ty_info.rust_obj + "_to_java(_env, ", ");"),

-                            ret_conv_name = ty_info.var_name + "_conv")
+                            ret_conv_name = ty_info.var_name + "_conv", to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

                     if ty_info.rust_obj in opaque_structs:
                     if ty_info.rust_obj in opaque_structs:

-                        ret_conv_suf = ";\nDO_ASSERT((((long)" + ty_info.var_name + "_var.inner) & 1) == 0); // We rely on a free low bit, malloc guarantees this.\n"
-                        ret_conv_suf = ret_conv_suf + "DO_ASSERT((((long)&" + ty_info.var_name + "_var) & 1) == 0); // We rely on a free low bit, pointer alignment guarantees this.\n"
+                        ret_conv_suf = ";\nCHECK((((long)" + ty_info.var_name + "_var.inner) & 1) == 0); // We rely on a free low bit, malloc guarantees this.\n"
+                        ret_conv_suf = ret_conv_suf + "CHECK((((long)&" + ty_info.var_name + "_var) & 1) == 0); // We rely on a free low bit, pointer alignment guarantees this.\n"

                         ret_conv_suf = ret_conv_suf + "long " + ty_info.var_name + "_ref;\n"
                         ret_conv_suf = ret_conv_suf + "if (" + ty_info.var_name + "_var.is_owned) {\n"
                         ret_conv_suf = ret_conv_suf + "\t" + ty_info.var_name + "_ref = (long)" + ty_info.var_name + "_var.inner | 1;\n"
                         ret_conv_suf = ret_conv_suf + "long " + ty_info.var_name + "_ref;\n"
                         ret_conv_suf = ret_conv_suf + "if (" + ty_info.var_name + "_var.is_owned) {\n"
                         ret_conv_suf = ret_conv_suf + "\t" + ty_info.var_name + "_ref = (long)" + ty_info.var_name + "_var.inner | 1;\n"


@@ -220,9 +534,12 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
                         ret_conv_suf = ret_conv_suf + "\t" + ty_info.var_name + "_ref = (long)&" + ty_info.var_name + "_var;\n"
                         ret_conv_suf = ret_conv_suf + "}"
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         ret_conv_suf = ret_conv_suf + "\t" + ty_info.var_name + "_ref = (long)&" + ty_info.var_name + "_var;\n"
                         ret_conv_suf = ret_conv_suf + "}"
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                            arg_conv = opaque_arg_conv, arg_conv_name = ty_info.var_name + "_conv",
+                            arg_conv = opaque_arg_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,

                             ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = ", ret_conv_suf),
                             ret_conv = (ty_info.rust_obj + " " + ty_info.var_name + "_var = ", ret_conv_suf),

-                            ret_conv_name = ty_info.var_name + "_ref")
+                            ret_conv_name = ty_info.var_name + "_ref",
+                            to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = new " + ty_info.java_hu_ty + "(null, " + ty_info.var_name + ");",
+                            to_hu_conv_name = ty_info.var_name + "_hu_conv",
+                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr & ~1", "this.ptrs_to.add(" + ty_info.var_name + ")"))

                     base_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)" + ty_info.var_name + ";";
                     if ty_info.rust_obj in trait_structs:
                         if not is_free:
                     base_conv = ty_info.rust_obj + " " + ty_info.var_name + "_conv = *(" + ty_info.rust_obj + "*)" + ty_info.var_name + ";";
                     if ty_info.rust_obj in trait_structs:
                         if not is_free:


@@ -232,86 +549,146 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
                         else:
                             base_conv = base_conv + "\n" + "FREE((void*)" + ty_info.var_name + ");"
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         else:
                             base_conv = base_conv + "\n" + "FREE((void*)" + ty_info.var_name + ");"
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                            arg_conv = base_conv,
-                            arg_conv_name = ty_info.var_name + "_conv",
-                            ret_conv = ("CANT PASS TRAIT TO Java?", ""), ret_conv_name = "NO CONV POSSIBLE")
+                            arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                            ret_conv = ("CANT PASS TRAIT TO Java?", ""), ret_conv_name = "NO CONV POSSIBLE",
+                            to_hu_conv = "DUMMY", to_hu_conv_name = None,
+                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr", "this.ptrs_to.add(" + ty_info.var_name + ")"))

                     if ty_info.rust_obj != "LDKu8slice":
                         # Don't bother free'ing slices passed in - Rust doesn't auto-free the
                         # underlying unlike Vecs, and it gives Java more freedom.
                         base_conv = base_conv + "\nFREE((void*)" + ty_info.var_name + ");";
                     if ty_info.rust_obj != "LDKu8slice":
                         # Don't bother free'ing slices passed in - Rust doesn't auto-free the
                         # underlying unlike Vecs, and it gives Java more freedom.
                         base_conv = base_conv + "\nFREE((void*)" + ty_info.var_name + ");";

+                    if ty_info.rust_obj in complex_enums:
+                        return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                            arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                            ret_conv = ("long " + ty_info.var_name + "_ref = (long)&", ";"), ret_conv_name = ty_info.var_name + "_ref",
+                            to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = " + ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ");",
+                            to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = (ty_info.var_name + ".conv_to_c()", ""))
+                    if ty_info.rust_obj in tuple_types:
+                        to_hu_conv_pfx = ""
+                        to_hu_conv_sfx = ty_info.java_hu_ty + " " + ty_info.var_name + "_conv = new " + ty_info.java_hu_ty + "("
+                        for idx, conv in enumerate(tuple_types[ty_info.rust_obj][0]):
+                            if idx != 0:
+                                to_hu_conv_sfx = to_hu_conv_sfx + ", "
+                            conv.var_name = ty_info.var_name + "_" + chr(idx + ord("a"))
+                            conv_map = map_type_with_info(conv, False, None, is_free)
+                            to_hu_conv_pfx = to_hu_conv_pfx + conv.java_ty + " " + ty_info.var_name + "_" + chr(idx + ord("a")) + " = " + "bindings." + tuple_types[ty_info.rust_obj][1] + "_get_" + chr(idx + ord("a")) + "(" + ty_info.var_name + ");\n"
+                            if conv_map.to_hu_conv is not None:
+                                to_hu_conv_pfx = to_hu_conv_pfx + conv_map.to_hu_conv + ";\n"
+                                to_hu_conv_sfx = to_hu_conv_sfx + conv_map.to_hu_conv_name;
+                            else:
+                                to_hu_conv_sfx = to_hu_conv_sfx + ty_info.var_name + "_" + chr(idx + ord("a"));
+                        return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                            arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                            ret_conv = ("long " + ty_info.var_name + "_ref = (long)&", ";"), ret_conv_name = ty_info.var_name + "_ref",
+                            to_hu_conv = to_hu_conv_pfx + to_hu_conv_sfx + ");", to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = ("/*TODO b*/0", ""))
+
+                    # The manually-defined types - TxOut and Transaction

                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                        arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv",
-                        ret_conv = ("long " + ty_info.var_name + "_ref = (long)&", ";"), ret_conv_name = ty_info.var_name + "_ref")
+                        arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                        ret_conv = ("long " + ty_info.var_name + "_ref = (long)&", ";"), ret_conv_name = ty_info.var_name + "_ref",
+                        to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_conv = new " +ty_info.java_hu_ty + "(null, " + ty_info.var_name + ");",
+                        to_hu_conv_name = ty_info.var_name + "_conv", from_hu_conv = ("/*TODO 1*/0", ""))

                 else:
                     assert(not is_free)
                     if ty_info.rust_obj in opaque_structs:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                 else:
                     assert(not is_free)
                     if ty_info.rust_obj in opaque_structs:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                            arg_conv = opaque_arg_conv, arg_conv_name = "&" + ty_info.var_name + "_conv",
-                            ret_conv = None, ret_conv_name = None) # its a pointer, no conv needed
+                            arg_conv = opaque_arg_conv, arg_conv_name = "&" + ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                            ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 2", to_hu_conv_name = None,
+                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr & ~1", "this.ptrs_to.add(" + ty_info.var_name + ")")) # its a pointer, no conv needed
+                    elif ty_info.rust_obj in trait_structs:
+                        return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                            arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + ";",
+                            arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                            ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 2.5", to_hu_conv_name = None,
+                            from_hu_conv = (ty_info.var_name + " == null ? 0 : " + ty_info.var_name + ".ptr", "this.ptrs_to.add(" + ty_info.var_name + ")")) # its a pointer, no conv needed

                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + ";",
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         arg_conv = ty_info.rust_obj + "* " + ty_info.var_name + "_conv = (" + ty_info.rust_obj + "*)" + ty_info.var_name + ";",

-                        arg_conv_name = ty_info.var_name + "_conv",
-                        ret_conv = None, ret_conv_name = None) # its a pointer, no conv needed
+                        arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
+                        ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 3", to_hu_conv_name = None, from_hu_conv = None) # its a pointer, no conv needed

             elif ty_info.is_ptr:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
             elif ty_info.is_ptr:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                    arg_conv = None, arg_conv_name = ty_info.var_name, ret_conv = None, ret_conv_name = None)
-            elif ty_info.java_ty == "String":
-                return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
-                    arg_conv = None, arg_conv_name = None,
-                    ret_conv = ("jstring " + ty_info.var_name + "_conv = (*_env)->NewStringUTF(_env, ", ");"), ret_conv_name = ty_info.var_name + "_conv")
+                    arg_conv = None, arg_conv_name = ty_info.var_name, arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 4", to_hu_conv_name = None, from_hu_conv = None)

             else:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
             else:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                    arg_conv = None, arg_conv_name = ty_info.var_name, ret_conv = None, ret_conv_name = None)
+                    arg_conv = None, arg_conv_name = ty_info.var_name, arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None, to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

         elif not print_void:
             # We don't have a parameter name, and want one, just call it arg
             if ty_info.rust_obj is not None:
         elif not print_void:
             # We don't have a parameter name, and want one, just call it arg
             if ty_info.rust_obj is not None:

-                assert(not is_free or ty_info.rust_obj not in opaque_structs);
+                assert(not is_free or ty_info.rust_obj not in opaque_structs)

                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                     arg_conv = ty_info.rust_obj + " arg_conv = *(" + ty_info.rust_obj + "*)arg;\nFREE((void*)arg);",
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                     arg_conv = ty_info.rust_obj + " arg_conv = *(" + ty_info.rust_obj + "*)arg;\nFREE((void*)arg);",

-                    arg_conv_name = "arg_conv",
-                    ret_conv = None, ret_conv_name = None)
+                    arg_conv_name = "arg_conv", arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 7", to_hu_conv_name = None, from_hu_conv = None)

             else:
                 assert(not is_free)
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
             else:
                 assert(not is_free)
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                    arg_conv = None, arg_conv_name = "arg", ret_conv = None, ret_conv_name = None)
+                    arg_conv = None, arg_conv_name = "arg", arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None, to_hu_conv = "TODO 8", to_hu_conv_name = None, from_hu_conv = None)

         else:
             # We don't have a parameter name, and don't want one (cause we're returning)
             if ty_info.rust_obj is not None:
                 if not ty_info.is_ptr:
                     if ty_info.rust_obj in unitary_enums:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
         else:
             # We don't have a parameter name, and don't want one (cause we're returning)
             if ty_info.rust_obj is not None:
                 if not ty_info.is_ptr:
                     if ty_info.rust_obj in unitary_enums:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                            arg_conv = ty_info.rust_obj + " ret = " + ty_info.rust_obj + "_from_java(_env, " + ty_info.var_name + ");",
-                            arg_conv_name = "ret",
-                            ret_conv = ("jclass ret = " + ty_info.rust_obj + "_to_java(_env, ", ");"), ret_conv_name = "ret")
+                            arg_conv = ty_info.rust_obj + " ret_conv = " + ty_info.rust_obj + "_from_java(_env, ret);",
+                            arg_conv_name = "ret_conv", arg_conv_cleanup = None,
+                            ret_conv = ("jclass ret = " + ty_info.rust_obj + "_to_java(_env, ", ");"), ret_conv_name = "ret",
+                            to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

                     if ty_info.rust_obj in opaque_structs:
                         # If we're returning a newly-allocated struct, we don't want Rust to ever
                         # free, instead relying on the Java GC to lose the ref. We undo this in
                         # any _free function.
                         # To avoid any issues, we first assert that the incoming object is non-ref.
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                     if ty_info.rust_obj in opaque_structs:
                         # If we're returning a newly-allocated struct, we don't want Rust to ever
                         # free, instead relying on the Java GC to lose the ref. We undo this in
                         # any _free function.
                         # To avoid any issues, we first assert that the incoming object is non-ref.
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                            ret_conv = (ty_info.rust_obj + " ret = ", ";\nDO_ASSERT(ret.is_owned);"),
-                            ret_conv_name = "((long)ret.inner) | 1",
-                            arg_conv = None, arg_conv_name = None)
+                            ret_conv = (ty_info.rust_obj + " ret = ", ";"),
+                            ret_conv_name = "((long)ret.inner) | (ret.is_owned ? 1 : 0)",
+                            arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                            to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, ret);",
+                            to_hu_conv_name = "ret_hu_conv", from_hu_conv = None)
+                    elif ty_info.rust_obj in trait_structs:
+                        return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                            ret_conv = (ty_info.rust_obj + "* ret = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*ret = ", ";"),
+                            ret_conv_name = "(long)ret",
+                            arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                            to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, ret);\nret_hu_conv.ptrs_to.add(this);",
+                            to_hu_conv_name = "ret_hu_conv", from_hu_conv = None)

                     else:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                             ret_conv = (ty_info.rust_obj + "* ret = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*ret = ", ";"),
                             ret_conv_name = "(long)ret",
                     else:
                         return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                             ret_conv = (ty_info.rust_obj + "* ret = MALLOC(sizeof(" + ty_info.rust_obj + "), \"" + ty_info.rust_obj + "\");\n*ret = ", ";"),
                             ret_conv_name = "(long)ret",

-                            arg_conv = None, arg_conv_name = None)
+                            arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                            to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, ret);\nret_hu_conv.ptrs_to.add(this);",
+                            to_hu_conv_name = "ret_hu_conv", from_hu_conv = None)
+                elif ty_info.rust_obj in trait_structs:
+                    return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
+                        ret_conv = ("long ret = (long)", ";"), ret_conv_name = "ret",
+                        arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                        to_hu_conv = ty_info.java_hu_ty + " ret_hu_conv = new " + ty_info.java_hu_ty + "(null, ret);\nret_hu_conv.ptrs_to.add(this);",
+                        to_hu_conv_name = "ret_hu_conv", from_hu_conv = None)

                 else:
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         ret_conv = ("long ret = (long)", ";"), ret_conv_name = "ret",
                 else:
                     return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
                         ret_conv = ("long ret = (long)", ";"), ret_conv_name = "ret",

-                        arg_conv = None, arg_conv_name = None)
+                        arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                        to_hu_conv = "TODO c", to_hu_conv_name = None, from_hu_conv = None)

             else:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,
             else:
                 return ConvInfo(ty_info = ty_info, arg_name = ty_info.var_name,

-                    arg_conv = None, arg_conv_name = None, ret_conv = None, ret_conv_name = None)
+                    arg_conv = None, arg_conv_name = None, arg_conv_cleanup = None,
+                    ret_conv = None, ret_conv_name = None,
+                    to_hu_conv = None, to_hu_conv_name = None, from_hu_conv = None)

 
     def map_fn(line, re_match, ret_arr_len, c_call_string):
         out_java.write("\t// " + line)
         out_java.write("\tpublic static native ")
         out_c.write("JNIEXPORT ")
 
 
     def map_fn(line, re_match, ret_arr_len, c_call_string):
         out_java.write("\t// " + line)
         out_java.write("\tpublic static native ")
         out_c.write("JNIEXPORT ")
 

+        is_free = re_match.group(2).endswith("_free")
+        struct_meth = re_match.group(2).split("_")[0]
+

         ret_info = map_type(re_match.group(1), True, ret_arr_len, False)
         ret_info.print_ty()
         ret_info = map_type(re_match.group(1), True, ret_arr_len, False)
         ret_info.print_ty()

+

         if ret_info.ret_conv is not None:
             ret_conv_pfx, ret_conv_sfx = ret_info.ret_conv
 
         if ret_info.ret_conv is not None:
             ret_conv_pfx, ret_conv_sfx = ret_info.ret_conv
 


@@ -319,28 +696,86 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
         out_c.write(" JNICALL Java_org_ldk_impl_bindings_" + re_match.group(2).replace('_', '_1') + "(JNIEnv * _env, jclass _b")
 
         arg_names = []
         out_c.write(" JNICALL Java_org_ldk_impl_bindings_" + re_match.group(2).replace('_', '_1') + "(JNIEnv * _env, jclass _b")
 
         arg_names = []

+        default_constructor_args = {}
+        takes_self = False
+        args_known = not ret_info.passed_as_ptr or ret_info.rust_obj in opaque_structs or ret_info.rust_obj in trait_structs

         for idx, arg in enumerate(re_match.group(3).split(',')):
             if idx != 0:
                 out_java.write(", ")
             if arg != "void":
                 out_c.write(", ")
         for idx, arg in enumerate(re_match.group(3).split(',')):
             if idx != 0:
                 out_java.write(", ")
             if arg != "void":
                 out_c.write(", ")

-            arg_conv_info = map_type(arg, False, None, re_match.group(2).endswith("_free"))
+            arg_conv_info = map_type(arg, False, None, is_free)

             if arg_conv_info.c_ty != "void":
                 arg_conv_info.print_ty()
                 arg_conv_info.print_name()
             if arg_conv_info.c_ty != "void":
                 arg_conv_info.print_ty()
                 arg_conv_info.print_name()

+            if arg_conv_info.arg_name == "this_ptr" or arg_conv_info.arg_name == "this_arg":
+                takes_self = True
+            if arg_conv_info.passed_as_ptr and not arg_conv_info.rust_obj in opaque_structs:
+                if not arg_conv_info.rust_obj in trait_structs and not arg_conv_info.rust_obj in unitary_enums:
+                    args_known = False
+            if arg_conv_info.arg_conv is not None and "Warning" in arg_conv_info.arg_conv:
+                if arg_conv_info.rust_obj in constructor_fns:
+                    assert not is_free
+                    for explode_arg in constructor_fns[arg_conv_info.rust_obj].split(','):
+                        explode_arg_conv = map_type(explode_arg, False, None, False)
+                        if explode_arg_conv.c_ty == "void":
+                            # We actually want to handle this case, but for now its only used in NetGraphMsgHandler::new()
+                            # which ends up resulting in a redundant constructor - both without arguments for the NetworkGraph.
+                            args_known = False
+                        assert explode_arg_conv.arg_name != "this_ptr"
+                        assert explode_arg_conv.arg_name != "this_arg"
+                        if explode_arg_conv.passed_as_ptr and not explode_arg_conv.rust_obj in trait_structs:
+                            args_known = False
+                        if not arg_conv_info.arg_name in default_constructor_args:
+                            default_constructor_args[arg_conv_info.arg_name] = []
+                        default_constructor_args[arg_conv_info.arg_name].append(explode_arg_conv)
+                else:
+                    args_known = False

             arg_names.append(arg_conv_info)
 
             arg_names.append(arg_conv_info)
 

+        out_java_struct = None
+        if ("LDK" + struct_meth in opaque_structs or "LDK" + struct_meth in trait_structs) and not is_free:
+            out_java_struct = open(sys.argv[3] + "/structs/" + struct_meth + ".java", "a")
+            if not args_known:
+                out_java_struct.write("\t// Skipped " + re_match.group(2) + "\n")
+                out_java_struct.close()
+                out_java_struct = None
+            else:
+                meth_n = re_match.group(2)[len(struct_meth) + 1:]
+                if ret_info.rust_obj == "LDK" + struct_meth:
+                    out_java_struct.write("\tpublic static " + ret_info.java_hu_ty + " constructor_" + meth_n + "(")
+                else:
+                    out_java_struct.write("\tpublic " + ret_info.java_hu_ty + " " + meth_n + "(")
+                for idx, arg in enumerate(arg_names):
+                    if idx != 0:
+                        if not takes_self or idx > 1:
+                            out_java_struct.write(", ")
+                    if arg.java_ty != "void" and arg.arg_name != "this_ptr" and arg.arg_name != "this_arg":
+                        if arg.arg_name in default_constructor_args:
+                            for explode_idx, explode_arg in enumerate(default_constructor_args[arg.arg_name]):
+                                if explode_idx != 0:
+                                    out_java_struct.write(", ")
+                                assert explode_arg.rust_obj in opaque_structs or explode_arg.rust_obj in trait_structs
+                                out_java_struct.write(explode_arg.java_hu_ty + " " + arg.arg_name + "_" + explode_arg.arg_name)
+                        else:
+                            out_java_struct.write(arg.java_hu_ty + " " + arg.arg_name)
+
+

         out_java.write(");\n")
         out_c.write(") {\n")
         out_java.write(");\n")
         out_c.write(") {\n")

+        if out_java_struct is not None:
+            out_java_struct.write(") {\n")

 
         for info in arg_names:
             if info.arg_conv is not None:
 
         for info in arg_names:
             if info.arg_conv is not None:

-                out_c.write("\t" + info.arg_conv.replace('\n', "\n\t") + "\n");
+                out_c.write("\t" + info.arg_conv.replace('\n', "\n\t") + "\n")

 
         if ret_info.ret_conv is not None:
 
         if ret_info.ret_conv is not None:

-            out_c.write("\t" + ret_conv_pfx.replace('\n', '\n\t'));
+            out_c.write("\t" + ret_conv_pfx.replace('\n', '\n\t'))
+        elif ret_info.c_ty != "void":
+            out_c.write("\t" + ret_info.c_ty + " ret_val = ")

         else:
         else:

-            out_c.write("\treturn ");
+            out_c.write("\t")

 
         if c_call_string is None:
             out_c.write(re_match.group(2) + "(")
 
         if c_call_string is None:
             out_c.write(re_match.group(2) + "(")


@@ -356,13 +791,64 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
         out_c.write(")")
         if ret_info.ret_conv is not None:
             out_c.write(ret_conv_sfx.replace('\n', '\n\t'))
         out_c.write(")")
         if ret_info.ret_conv is not None:
             out_c.write(ret_conv_sfx.replace('\n', '\n\t'))

-            out_c.write("\n\treturn " + ret_info.ret_conv_name + ";")

         else:
             out_c.write(";")
         else:
             out_c.write(";")

+        for info in arg_names:
+            if info.arg_conv_cleanup is not None:
+                out_c.write("\n\t" + info.arg_conv_cleanup.replace("\n", "\n\t"))
+        if ret_info.ret_conv is not None:
+            out_c.write("\n\treturn " + ret_info.ret_conv_name + ";")
+        elif ret_info.c_ty != "void":
+            out_c.write("\n\treturn ret_val;")

         out_c.write("\n}\n\n")
         out_c.write("\n}\n\n")

+        if out_java_struct is not None:
+            out_java_struct.write("\t\t")
+            if ret_info.java_ty != "void":
+                out_java_struct.write(ret_info.java_ty + " ret = ")
+            out_java_struct.write("bindings." + re_match.group(2) + "(")
+            for idx, info in enumerate(arg_names):
+                if idx != 0:
+                    out_java_struct.write(", ")
+                if info.arg_name == "this_ptr" or info.arg_name == "this_arg":
+                    out_java_struct.write("this.ptr")
+                elif info.arg_name in default_constructor_args:
+                    out_java_struct.write("bindings." + info.java_hu_ty + "_new(")
+                    for explode_idx, explode_arg in enumerate(default_constructor_args[info.arg_name]):
+                        if explode_idx != 0:
+                            out_java_struct.write(", ")
+                        expl_arg_name = info.arg_name + "_" + explode_arg.arg_name
+                        out_java_struct.write(explode_arg.from_hu_conv[0].replace(explode_arg.arg_name, expl_arg_name))
+                    out_java_struct.write(")")
+                elif info.from_hu_conv is not None:
+                    out_java_struct.write(info.from_hu_conv[0])
+                else:
+                    out_java_struct.write(info.arg_name)
+            out_java_struct.write(");\n")
+            if ret_info.to_hu_conv is not None:
+                out_java_struct.write("\t\t" + ret_info.to_hu_conv.replace("\n", "\n\t\t") + "\n")
+
+            for info in arg_names:
+                if info.arg_name == "this_ptr" or info.arg_name == "this_arg":
+                    pass
+                elif info.arg_name in default_constructor_args:
+                    for explode_arg in default_constructor_args[info.arg_name]:
+                        expl_arg_name = info.arg_name + "_" + explode_arg.arg_name
+                        out_java_struct.write("\t\t" + explode_arg.from_hu_conv[1].replace(explode_arg.arg_name, expl_arg_name).replace("this", ret_info.to_hu_conv_name) + ";\n")
+                elif info.from_hu_conv is not None and info.from_hu_conv[1] != "":
+                    if ret_info.rust_obj == "LDK" + struct_meth and ret_info.to_hu_conv_name is not None:
+                        out_java_struct.write("\t\t" + info.from_hu_conv[1].replace("this", ret_info.to_hu_conv_name) + ";\n")
+                    else:
+                        out_java_struct.write("\t\t" + info.from_hu_conv[1] + ";\n")
+
+            if ret_info.to_hu_conv_name is not None:
+                out_java_struct.write("\t\treturn " + ret_info.to_hu_conv_name + ";\n")
+            elif ret_info.java_ty != "void" and ret_info.rust_obj != "LDK" + struct_meth:
+                out_java_struct.write("\t\treturn ret;\n")
+            out_java_struct.write("\t}\n\n")
+            out_java_struct.close()

 
     def map_unitary_enum(struct_name, field_lines):
 
     def map_unitary_enum(struct_name, field_lines):

-        with open(sys.argv[3] + "/" + struct_name + ".java", "w") as out_java_enum:
+        with open(sys.argv[3] + "/enums/" + struct_name + ".java", "w") as out_java_enum:

             out_java_enum.write("package org.ldk.enums;\n\n")
             unitary_enums.add(struct_name)
             out_c.write("static inline " + struct_name + " " + struct_name + "_from_java(JNIEnv *env, jclass val) {\n")
             out_java_enum.write("package org.ldk.enums;\n\n")
             unitary_enums.add(struct_name)
             out_c.write("static inline " + struct_name + " " + struct_name + "_from_java(JNIEnv *env, jclass val) {\n")


@@ -396,12 +882,12 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
                     out_c.write("static jfieldID " + struct_name + "_" + variant + " = NULL;\n")
             out_c.write("JNIEXPORT void JNICALL Java_org_ldk_enums_" + struct_name.replace("_", "_1") + "_init (JNIEnv * env, jclass clz) {\n")
             out_c.write("\t" + struct_name + "_class = (*env)->NewGlobalRef(env, clz);\n")
                     out_c.write("static jfieldID " + struct_name + "_" + variant + " = NULL;\n")
             out_c.write("JNIEXPORT void JNICALL Java_org_ldk_enums_" + struct_name.replace("_", "_1") + "_init (JNIEnv * env, jclass clz) {\n")
             out_c.write("\t" + struct_name + "_class = (*env)->NewGlobalRef(env, clz);\n")

-            out_c.write("\tDO_ASSERT(" + struct_name + "_class != NULL);\n")
+            out_c.write("\tCHECK(" + struct_name + "_class != NULL);\n")

             for idx, struct_line in enumerate(field_lines):
                 if idx > 0 and idx < len(field_lines) - 3:
                     variant = struct_line.strip().strip(",")
                     out_c.write("\t" + struct_name + "_" + variant + " = (*env)->GetStaticFieldID(env, " + struct_name + "_class, \"" + variant + "\", \"Lorg/ldk/enums/" + struct_name + ";\");\n")
             for idx, struct_line in enumerate(field_lines):
                 if idx > 0 and idx < len(field_lines) - 3:
                     variant = struct_line.strip().strip(",")
                     out_c.write("\t" + struct_name + "_" + variant + " = (*env)->GetStaticFieldID(env, " + struct_name + "_class, \"" + variant + "\", \"Lorg/ldk/enums/" + struct_name + ";\");\n")

-                    out_c.write("\tDO_ASSERT(" + struct_name + "_" + variant + " != NULL);\n")
+                    out_c.write("\tCHECK(" + struct_name + "_" + variant + " != NULL);\n")

             out_c.write("}\n")
             out_c.write("static inline jclass " + struct_name + "_to_java(JNIEnv *env, " + struct_name + " val) {\n")
             out_c.write("\tswitch (val) {\n")
             out_c.write("}\n")
             out_c.write("static inline jclass " + struct_name + "_to_java(JNIEnv *env, " + struct_name + " val) {\n")
             out_c.write("\tswitch (val) {\n")


@@ -416,245 +902,307 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
             out_c.write("}\n\n")
 
     def map_complex_enum(struct_name, union_enum_items):
             out_c.write("}\n\n")
 
     def map_complex_enum(struct_name, union_enum_items):

-        tag_field_lines = union_enum_items["field_lines"]
-        init_meth_jty_strs = {}
-        for idx, struct_line in enumerate(tag_field_lines):
-            if idx == 0:
-                out_java.write("\tpublic static class " + struct_name + " {\n")
-                out_java.write("\t\tprivate " + struct_name + "() {}\n")
-            elif idx == len(tag_field_lines) - 3:
-                assert(struct_line.endswith("_Sentinel,"))
-            elif idx == len(tag_field_lines) - 2:
-                out_java.write("\t\tstatic native void init();\n")
-                out_java.write("\t}\n")
-            elif idx == len(tag_field_lines) - 1:
-                assert(struct_line == "")
-            else:
-                var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
-                out_java.write("\t\tpublic final static class " + var_name + " extends " + struct_name + " {\n")
-                out_c.write("static jclass " + struct_name + "_" + var_name + "_class = NULL;\n")
-                out_c.write("static jmethodID " + struct_name + "_" + var_name + "_meth = NULL;\n")
-                init_meth_jty_str = ""
-                init_meth_params = ""
-                init_meth_body = ""
-                if "LDK" + var_name in union_enum_items:
-                    enum_var_lines = union_enum_items["LDK" + var_name]
-                    for idx, field in enumerate(enum_var_lines):
-                        if idx != 0 and idx < len(enum_var_lines) - 2:
-                            field_ty = java_c_types(field.strip(' ;'), None)
-                            out_java.write("\t\t\tpublic " + field_ty.java_ty + " " + field_ty.var_name + ";\n")
-                            init_meth_jty_str = init_meth_jty_str + field_ty.java_fn_ty_arg
-                            if idx > 1:
-                                init_meth_params = init_meth_params + ", "
-                            init_meth_params = init_meth_params + field_ty.java_ty + " " + field_ty.var_name
-                            init_meth_body = init_meth_body + "this." + field_ty.var_name + " = " + field_ty.var_name + "; "
-                    out_java.write("\t\t\t" + var_name + "(" + init_meth_params + ") { ")
-                    out_java.write(init_meth_body)
-                    out_java.write("}\n")
-                out_java.write("\t\t}\n")
-                init_meth_jty_strs[var_name] = init_meth_jty_str
-        out_java.write("\tstatic { " + struct_name + ".init(); }\n")
-        out_java.write("\tpublic static native " + struct_name + " " + struct_name + "_ref_from_ptr(long ptr);\n");
-
-        out_c.write("JNIEXPORT void JNICALL Java_org_ldk_impl_bindings_00024" + struct_name.replace("_", "_1") + "_init (JNIEnv * env, jclass _a) {\n")
-        for idx, struct_line in enumerate(tag_field_lines):
-            if idx != 0 and idx < len(tag_field_lines) - 3:
-                var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
-                out_c.write("\t" + struct_name + "_" + var_name + "_class =\n")
-                out_c.write("\t\t(*env)->NewGlobalRef(env, (*env)->FindClass(env, \"Lorg/ldk/impl/bindings$" + struct_name + "$" + var_name + ";\"));\n")
-                out_c.write("\tDO_ASSERT(" + struct_name + "_" + var_name + "_class != NULL);\n")
-                out_c.write("\t" + struct_name + "_" + var_name + "_meth = (*env)->GetMethodID(env, " + struct_name + "_" + var_name + "_class, \"<init>\", \"(" + init_meth_jty_strs[var_name] + ")V\");\n")
-                out_c.write("\tDO_ASSERT(" + struct_name + "_" + var_name + "_meth != NULL);\n")
-        out_c.write("}\n")
-        out_c.write("JNIEXPORT jobject JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1ref_1from_1ptr (JNIEnv * env, jclass _c, jlong ptr) {\n")
-        out_c.write("\t" + struct_name + " *obj = (" + struct_name + "*)ptr;\n")
-        out_c.write("\tswitch(obj->tag) {\n")
-        for idx, struct_line in enumerate(tag_field_lines):
-            if idx != 0 and idx < len(tag_field_lines) - 3:
-                var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
-                out_c.write("\t\tcase " + struct_name + "_" + var_name + ": {\n")
-                c_params_text = ""
-                if "LDK" + var_name in union_enum_items:
-                    enum_var_lines = union_enum_items["LDK" + var_name]
-                    for idx, field in enumerate(enum_var_lines):
-                        if idx != 0 and idx < len(enum_var_lines) - 2:
-                            field_map = map_type(field.strip(' ;'), False, None, False)
-                            if field_map.ret_conv is not None:
-                                out_c.write("\t\t\t" + field_map.ret_conv[0].replace("\n", "\n\t\t\t").replace("_env", "env"))
-                                out_c.write("obj->" + camel_to_snake(var_name) + "." + field_map.arg_name)
-                                out_c.write(field_map.ret_conv[1].replace("\n", "\n\t\t\t") + "\n")
-                                c_params_text = c_params_text + ", " + field_map.ret_conv_name
-                            else:
-                                c_params_text = c_params_text + ", obj->" + camel_to_snake(var_name) + "." + field_map.arg_name
-                out_c.write("\t\t\treturn (*env)->NewObject(env, " + struct_name + "_" + var_name + "_class, " + struct_name + "_" + var_name + "_meth" + c_params_text + ");\n")
-                out_c.write("\t\t}\n")
-        out_c.write("\t\tdefault: abort();\n")
-        out_c.write("\t}\n}\n")
+        java_hu_type = struct_name.replace("LDK", "")
+        complex_enums.add(struct_name)
+        with open(sys.argv[3] + "/structs/" + java_hu_type + ".java", "w") as out_java_enum:
+            out_java_enum.write(hu_struct_file_prefix)
+            out_java_enum.write("public class " + java_hu_type + " extends CommonBase {\n")
+            out_java_enum.write("\tprivate " + java_hu_type + "(Object _dummy, long ptr) { super(ptr); }\n")
+            out_java_enum.write("\tlong conv_to_c() { assert false; return 0; /* Should only be called on subclasses */ }\n")
+            out_java_enum.write("\tstatic " + java_hu_type + " constr_from_ptr(long ptr) {\n")
+            out_java_enum.write("\t\tbindings." + struct_name + " raw_val = bindings." + struct_name + "_ref_from_ptr(ptr);\n")
+            java_hu_subclasses = ""
+
+            tag_field_lines = union_enum_items["field_lines"]
+            init_meth_jty_strs = {}
+            for idx, struct_line in enumerate(tag_field_lines):
+                if idx == 0:
+                    out_java.write("\tpublic static class " + struct_name + " {\n")
+                    out_java.write("\t\tprivate " + struct_name + "() {}\n")
+                elif idx == len(tag_field_lines) - 3:
+                    assert(struct_line.endswith("_Sentinel,"))
+                elif idx == len(tag_field_lines) - 2:
+                    out_java.write("\t\tstatic native void init();\n")
+                    out_java.write("\t}\n")
+                elif idx == len(tag_field_lines) - 1:
+                    assert(struct_line == "")
+                else:
+                    var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
+                    out_java.write("\t\tpublic final static class " + var_name + " extends " + struct_name + " {\n")
+                    java_hu_subclasses = java_hu_subclasses + "\tpublic final static class " + var_name + " extends " + java_hu_type + " {\n"
+                    out_java_enum.write("\t\tif (raw_val.getClass() == bindings." + struct_name + "." + var_name + ".class) {\n")
+                    out_java_enum.write("\t\t\treturn new " + var_name + "(null, ptr);\n") # TODO: Conv values!
+                    out_c.write("static jclass " + struct_name + "_" + var_name + "_class = NULL;\n")
+                    out_c.write("static jmethodID " + struct_name + "_" + var_name + "_meth = NULL;\n")
+                    init_meth_jty_str = ""
+                    init_meth_params = ""
+                    init_meth_body = ""
+                    if "LDK" + var_name in union_enum_items:
+                        enum_var_lines = union_enum_items["LDK" + var_name]
+                        for idx, field in enumerate(enum_var_lines):
+                            if idx != 0 and idx < len(enum_var_lines) - 2:
+                                field_ty = java_c_types(field.strip(' ;'), None)
+                                out_java.write("\t\t\tpublic " + field_ty.java_ty + " " + field_ty.var_name + ";\n")
+                                java_hu_subclasses = java_hu_subclasses + "\t\tpublic " + field_ty.java_hu_ty + " " + field_ty.var_name + ";\n"
+                                init_meth_jty_str = init_meth_jty_str + field_ty.java_fn_ty_arg
+                                if idx > 1:
+                                    init_meth_params = init_meth_params + ", "
+                                init_meth_params = init_meth_params + field_ty.java_ty + " " + field_ty.var_name
+                                init_meth_body = init_meth_body + "this." + field_ty.var_name + " = " + field_ty.var_name + "; "
+                        out_java.write("\t\t\t" + var_name + "(" + init_meth_params + ") { ")
+                        out_java.write(init_meth_body)
+                        out_java.write("}\n")
+                    out_java.write("\t\t}\n")
+                    out_java_enum.write("\t\t}\n")
+                    java_hu_subclasses = java_hu_subclasses + "\t\tprivate " + var_name + "(Object _dummy, long ptr) { super(null, ptr); }\n"
+                    java_hu_subclasses = java_hu_subclasses + "\t\t@Override long conv_to_c() { return 0; /*XXX*/ }\n"
+                    java_hu_subclasses = java_hu_subclasses + "\t}\n"
+                    init_meth_jty_strs[var_name] = init_meth_jty_str
+            out_java_enum.write("\t\tassert false; return null; // Unreachable without extending the (internal) bindings interface\n\t}\n\n")
+            out_java_enum.write(java_hu_subclasses)
+            out_java.write("\tstatic { " + struct_name + ".init(); }\n")
+            out_java.write("\tpublic static native " + struct_name + " " + struct_name + "_ref_from_ptr(long ptr);\n");
+
+            out_c.write("JNIEXPORT void JNICALL Java_org_ldk_impl_bindings_00024" + struct_name.replace("_", "_1") + "_init (JNIEnv * env, jclass _a) {\n")
+            for idx, struct_line in enumerate(tag_field_lines):
+                if idx != 0 and idx < len(tag_field_lines) - 3:
+                    var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
+                    out_c.write("\t" + struct_name + "_" + var_name + "_class =\n")
+                    out_c.write("\t\t(*env)->NewGlobalRef(env, (*env)->FindClass(env, \"Lorg/ldk/impl/bindings$" + struct_name + "$" + var_name + ";\"));\n")
+                    out_c.write("\tCHECK(" + struct_name + "_" + var_name + "_class != NULL);\n")
+                    out_c.write("\t" + struct_name + "_" + var_name + "_meth = (*env)->GetMethodID(env, " + struct_name + "_" + var_name + "_class, \"<init>\", \"(" + init_meth_jty_strs[var_name] + ")V\");\n")
+                    out_c.write("\tCHECK(" + struct_name + "_" + var_name + "_meth != NULL);\n")
+            out_c.write("}\n")
+            out_c.write("JNIEXPORT jobject JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1ref_1from_1ptr (JNIEnv * _env, jclass _c, jlong ptr) {\n")
+            out_c.write("\t" + struct_name + " *obj = (" + struct_name + "*)ptr;\n")
+            out_c.write("\tswitch(obj->tag) {\n")
+            for idx, struct_line in enumerate(tag_field_lines):
+                if idx != 0 and idx < len(tag_field_lines) - 3:
+                    var_name = struct_line.strip(' ,')[len(struct_name) + 1:]
+                    out_c.write("\t\tcase " + struct_name + "_" + var_name + ": {\n")
+                    c_params_text = ""
+                    if "LDK" + var_name in union_enum_items:
+                        enum_var_lines = union_enum_items["LDK" + var_name]
+                        for idx, field in enumerate(enum_var_lines):
+                            if idx != 0 and idx < len(enum_var_lines) - 2:
+                                field_map = map_type(field.strip(' ;'), False, None, False)
+                                if field_map.ret_conv is not None:
+                                    out_c.write("\t\t\t" + field_map.ret_conv[0].replace("\n", "\n\t\t\t"))
+                                    out_c.write("obj->" + camel_to_snake(var_name) + "." + field_map.arg_name)
+                                    out_c.write(field_map.ret_conv[1].replace("\n", "\n\t\t\t") + "\n")
+                                    c_params_text = c_params_text + ", " + field_map.ret_conv_name
+                                else:
+                                    c_params_text = c_params_text + ", obj->" + camel_to_snake(var_name) + "." + field_map.arg_name
+                    out_c.write("\t\t\treturn (*_env)->NewObject(_env, " + struct_name + "_" + var_name + "_class, " + struct_name + "_" + var_name + "_meth" + c_params_text + ");\n")
+                    out_c.write("\t\t}\n")
+            out_c.write("\t\tdefault: abort();\n")
+            out_c.write("\t}\n}\n")
+            out_java_enum.write("}\n")

 
     def map_trait(struct_name, field_var_lines, trait_fn_lines):
 
     def map_trait(struct_name, field_var_lines, trait_fn_lines):

-        out_c.write("typedef struct " + struct_name + "_JCalls {\n")
-        out_c.write("\tatomic_size_t refcnt;\n")
-        out_c.write("\tJavaVM *vm;\n")
-        out_c.write("\tjobject o;\n")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write("\t" + var_line.group(1) + "_JCalls* " + var_line.group(2) + ";\n")
-        for fn_line in trait_fn_lines:
-            if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
-                out_c.write("\tjmethodID " + fn_line.group(2) + "_meth;\n")
-        out_c.write("} " + struct_name + "_JCalls;\n")
+        with open(sys.argv[3] + "/structs/" + struct_name.replace("LDK","") + ".java", "w") as out_java_trait:
+            out_c.write("typedef struct " + struct_name + "_JCalls {\n")
+            out_c.write("\tatomic_size_t refcnt;\n")
+            out_c.write("\tJavaVM *vm;\n")
+            out_c.write("\tjweak o;\n")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write("\t" + var_line.group(1) + "_JCalls* " + var_line.group(2) + ";\n")
+            for fn_line in trait_fn_lines:
+                if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
+                    out_c.write("\tjmethodID " + fn_line.group(2) + "_meth;\n")
+            out_c.write("} " + struct_name + "_JCalls;\n")
+
+            out_java_trait.write(hu_struct_file_prefix)
+            out_java_trait.write("public class " + struct_name.replace("LDK","") + " extends CommonBase {\n")
+            out_java_trait.write("\t" + struct_name.replace("LDK", "") + "(Object _dummy, long ptr) { super(ptr); }\n")
+            out_java_trait.write("\tpublic " + struct_name.replace("LDK", "") + "(bindings." + struct_name + " arg") # XXX: Should be priv ( but is currently used in tests
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_java_trait.write(", bindings." + var_line.group(1) + " " + var_line.group(2))
+            out_java_trait.write(") {\n")
+            out_java_trait.write("\t\tsuper(bindings." + struct_name + "_new(arg")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_java_trait.write(", " + var_line.group(2))
+            out_java_trait.write("));\n")
+            out_java_trait.write("\t\tthis.ptrs_to.add(arg);\n")
+            out_java_trait.write("\t}\n")
+            out_java_trait.write("\t@Override @SuppressWarnings(\"deprecation\")\n")
+            out_java_trait.write("\tprotected void finalize() throws Throwable {\n")
+            out_java_trait.write("\t\tbindings." + struct_name.replace("LDK","") + "_free(ptr); super.finalize();\n")
+            out_java_trait.write("\t}\n\n")
+
+            java_trait_constr = "\tpublic " + struct_name.replace("LDK", "") + "(" + struct_name.replace("LDK", "") + "Interface arg) {\n"
+            java_trait_constr = java_trait_constr + "\t\tthis(new bindings." + struct_name + "() {\n"
+            #out_java_trait.write("\tpublic static interface " + struct_name.replace("LDK", "") + "Interface {\n")
+            out_java.write("\tpublic interface " + struct_name + " {\n")
+            java_meths = []
+            for fn_line in trait_fn_lines:
+                java_meth_descr = "("
+                if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
+                    ret_ty_info = map_type(fn_line.group(1), True, None, False)
+
+                    out_java.write("\t\t " + ret_ty_info.java_ty + " " + fn_line.group(2) + "(")
+                    java_trait_constr = java_trait_constr + "\t\t\t@Override public " + ret_ty_info.java_ty + " " + fn_line.group(2) + "("
+                    #out_java_trait.write("\t\t" + ret_ty_info.java_hu_ty + " " + fn_line.group(2) + "(")
+                    is_const = fn_line.group(3) is not None
+                    out_c.write(fn_line.group(1) + fn_line.group(2) + "_jcall(")
+                    if is_const:
+                        out_c.write("const void* this_arg")
+                    else:
+                        out_c.write("void* this_arg")
+
+                    arg_names = []
+                    for idx, arg in enumerate(fn_line.group(4).split(',')):
+                        if arg == "":
+                            continue
+                        if idx >= 2:
+                            out_java.write(", ")
+                            java_trait_constr = java_trait_constr + ", "
+                            #out_java_trait.write(", ")
+                        out_c.write(", ")
+                        arg_conv_info = map_type(arg, True, None, False)
+                        out_c.write(arg.strip())
+                        out_java.write(arg_conv_info.java_ty + " " + arg_conv_info.arg_name)
+                        #out_java_trait.write(arg_conv_info.java_ty + " " + arg_conv_info.arg_name)
+                        java_trait_constr = java_trait_constr + arg_conv_info.java_ty + " " + arg_conv_info.arg_name
+                        arg_names.append(arg_conv_info)
+                        java_meth_descr = java_meth_descr + arg_conv_info.java_fn_ty_arg
+                    java_meth_descr = java_meth_descr + ")" + ret_ty_info.java_fn_ty_arg
+                    java_meths.append(java_meth_descr)

 
 

-        out_java.write("\tpublic interface " + struct_name + " {\n")
-        java_meths = []
-        for fn_line in trait_fn_lines:
-            java_meth_descr = "("
-            if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
-                ret_ty_info = java_c_types(fn_line.group(1), None)
-
-                out_java.write("\t\t " + ret_ty_info.java_ty + " " + fn_line.group(2) + "(")
-                is_const = fn_line.group(3) is not None
-                out_c.write(fn_line.group(1) + fn_line.group(2) + "_jcall(")
-                if is_const:
-                    out_c.write("const void* this_arg")
-                else:
-                    out_c.write("void* this_arg")
-
-                arg_names = []
-                for idx, arg in enumerate(fn_line.group(4).split(',')):
-                    if arg == "":
-                        continue
-                    if idx >= 2:
-                        out_java.write(", ")
-                    out_c.write(", ")
-                    arg_conv_info = map_type(arg, True, None, False)
-                    out_c.write(arg.strip())
-                    out_java.write(arg_conv_info.java_ty + " " + arg_conv_info.arg_name)
-                    arg_names.append(arg_conv_info)
-                    java_meth_descr = java_meth_descr + arg_conv_info.java_fn_ty_arg
-                java_meth_descr = java_meth_descr + ")" + ret_ty_info.java_fn_ty_arg
-                java_meths.append(java_meth_descr)
-
-                out_java.write(");\n")
-                out_c.write(") {\n")
-                out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
-                out_c.write("\tJNIEnv *env;\n")
-                out_c.write("\tDO_ASSERT((*j_calls->vm)->GetEnv(j_calls->vm, (void**)&env, JNI_VERSION_1_8) == JNI_OK);\n")
-
-                for arg_info in arg_names:
-                    if arg_info.ret_conv is not None:
-                        out_c.write("\t" + arg_info.ret_conv[0].replace('\n', '\n\t').replace("_env", "env"));
-                        out_c.write(arg_info.arg_name)
-                        out_c.write(arg_info.ret_conv[1].replace('\n', '\n\t').replace("_env", "env") + "\n")
-
-                if ret_ty_info.c_ty.endswith("Array"):
-                    assert(ret_ty_info.c_ty == "jbyteArray")
-                    out_c.write("\tjbyteArray jret = (*env)->CallObjectMethod(env, j_calls->o, j_calls->" + fn_line.group(2) + "_meth")
-                elif not ret_ty_info.passed_as_ptr:
-                    out_c.write("\treturn (*env)->Call" + ret_ty_info.java_ty.title() + "Method(env, j_calls->o, j_calls->" + fn_line.group(2) + "_meth")
+                    out_java.write(");\n")
+                    #out_java_trait.write(");\n")
+                    java_trait_constr = java_trait_constr + ") {\n"
+                    out_c.write(") {\n")
+                    out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
+                    out_c.write("\tJNIEnv *_env;\n")
+                    out_c.write("\tDO_ASSERT((*j_calls->vm)->GetEnv(j_calls->vm, (void**)&_env, JNI_VERSION_1_8) == JNI_OK);\n")
+
+                    for arg_info in arg_names:
+                        if arg_info.ret_conv is not None:
+                            out_c.write("\t" + arg_info.ret_conv[0].replace('\n', '\n\t'));
+                            out_c.write(arg_info.arg_name)
+                            out_c.write(arg_info.ret_conv[1].replace('\n', '\n\t') + "\n")
+
+                    out_c.write("\tjobject obj = (*_env)->NewLocalRef(_env, j_calls->o);\n\tCHECK(obj != NULL);\n")
+                    if ret_ty_info.c_ty.endswith("Array"):
+                        out_c.write("\t" + ret_ty_info.c_ty + " ret = (*_env)->CallObjectMethod(_env, obj, j_calls->" + fn_line.group(2) + "_meth")
+                    elif not ret_ty_info.passed_as_ptr:
+                        out_c.write("\treturn (*_env)->Call" + ret_ty_info.java_ty.title() + "Method(_env, obj, j_calls->" + fn_line.group(2) + "_meth")
+                    else:
+                        out_c.write("\t" + fn_line.group(1).strip() + "* ret = (" + fn_line.group(1).strip() + "*)(*_env)->CallLongMethod(_env, obj, j_calls->" + fn_line.group(2) + "_meth");
+                    if ret_ty_info.java_ty != "void":
+                        java_trait_constr = java_trait_constr + "\t\t\t\treturn arg." + fn_line.group(2) + "("
+                    else:
+                        java_trait_constr = java_trait_constr + "\t\t\t\targ." + fn_line.group(2) + "("
+
+                    for arg_info in arg_names:
+                        if arg_info.ret_conv is not None:
+                            out_c.write(", " + arg_info.ret_conv_name)
+                        else:
+                            out_c.write(", " + arg_info.arg_name)
+                    out_c.write(");\n");
+                    if ret_ty_info.arg_conv is not None:
+                        out_c.write("\t" + ret_ty_info.arg_conv.replace("\n", "\n\t").replace("arg", "ret") + "\n\treturn " + ret_ty_info.arg_conv_name.replace("arg", "ret") + ";\n")
+
+                    if ret_ty_info.passed_as_ptr:
+                        out_c.write("\t" + fn_line.group(1).strip() + " res = *ret;\n")
+                        out_c.write("\tFREE(ret);\n")
+                        out_c.write("\treturn res;\n")
+                    out_c.write("}\n")
+                    java_trait_constr = java_trait_constr + ");\n\t\t\t}\n"
+                elif fn_line.group(2) == "free":
+                    out_c.write("static void " + struct_name + "_JCalls_free(void* this_arg) {\n")
+                    out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
+                    out_c.write("\tif (atomic_fetch_sub_explicit(&j_calls->refcnt, 1, memory_order_acquire) == 1) {\n")
+                    out_c.write("\t\tJNIEnv *env;\n")
+                    out_c.write("\t\tDO_ASSERT((*j_calls->vm)->GetEnv(j_calls->vm, (void**)&env, JNI_VERSION_1_8) == JNI_OK);\n")
+                    out_c.write("\t\t(*env)->DeleteWeakGlobalRef(env, j_calls->o);\n")
+                    out_c.write("\t\tFREE(j_calls);\n")
+                    out_c.write("\t}\n}\n")
+            #out_java_trait.write("\t}\n")
+            #out_java_trait.write(java_trait_constr + "\t\t});\n\t}\n")
+
+            # Write out a clone function whether we need one or not, as we use them in moving to rust
+            out_c.write("static void* " + struct_name + "_JCalls_clone(const void* this_arg) {\n")
+            out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
+            out_c.write("\tatomic_fetch_add_explicit(&j_calls->refcnt, 1, memory_order_release);\n")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write("\tatomic_fetch_add_explicit(&j_calls->" + var_line.group(2) + "->refcnt, 1, memory_order_release);\n")
+            out_c.write("\treturn (void*) this_arg;\n")
+            out_c.write("}\n")
+
+            out_java.write("\t}\n")
+
+            out_java.write("\tpublic static native long " + struct_name + "_new(" + struct_name + " impl")
+            out_c.write("static inline " + struct_name + " " + struct_name + "_init (JNIEnv * env, jclass _a, jobject o")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_java.write(", " + var_line.group(1) + " " + var_line.group(2))
+                    out_c.write(", jobject " + var_line.group(2))
+            out_java.write(");\n")
+            out_c.write(") {\n")
+
+            out_c.write("\tjclass c = (*env)->GetObjectClass(env, o);\n")
+            out_c.write("\tCHECK(c != NULL);\n")
+            out_c.write("\t" + struct_name + "_JCalls *calls = MALLOC(sizeof(" + struct_name + "_JCalls), \"" + struct_name + "_JCalls\");\n")
+            out_c.write("\tatomic_init(&calls->refcnt, 1);\n")
+            out_c.write("\tDO_ASSERT((*env)->GetJavaVM(env, &calls->vm) == 0);\n")
+            out_c.write("\tcalls->o = (*env)->NewWeakGlobalRef(env, o);\n")
+            for (fn_line, java_meth_descr) in zip(trait_fn_lines, java_meths):
+                if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
+                    out_c.write("\tcalls->" + fn_line.group(2) + "_meth = (*env)->GetMethodID(env, c, \"" + fn_line.group(2) + "\", \"" + java_meth_descr + "\");\n")
+                    out_c.write("\tCHECK(calls->" + fn_line.group(2) + "_meth != NULL);\n")
+            out_c.write("\n\t" + struct_name + " ret = {\n")
+            out_c.write("\t\t.this_arg = (void*) calls,\n")
+            for fn_line in trait_fn_lines:
+                if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
+                    out_c.write("\t\t." + fn_line.group(2) + " = " + fn_line.group(2) + "_jcall,\n")
+                elif fn_line.group(2) == "free":
+                    out_c.write("\t\t.free = " + struct_name + "_JCalls_free,\n")

                 else:
                 else:

-                    out_c.write("\t" + fn_line.group(1).strip() + "* ret = (" + fn_line.group(1).strip() + "*)(*env)->CallLongMethod(env, j_calls->o, j_calls->" + fn_line.group(2) + "_meth");
+                    clone_fns.add(struct_name + "_clone")
+                    out_c.write("\t\t.clone = " + struct_name + "_JCalls_clone,\n")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write("\t\t." + var_line.group(2) + " = " + var_line.group(1) + "_init(env, _a, " + var_line.group(2) + "),\n")
+            out_c.write("\t};\n")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write("\tcalls->" + var_line.group(2) + " = ret." + var_line.group(2) + ".this_arg;\n")
+            out_c.write("\treturn ret;\n")
+            out_c.write("}\n")

 
 

-                for arg_info in arg_names:
-                    if arg_info.ret_conv is not None:
-                        out_c.write(", " + arg_info.ret_conv_name)
-                    else:
-                        out_c.write(", " + arg_info.arg_name)
-                out_c.write(");\n");
-                if ret_ty_info.c_ty.endswith("Array"):
-                    out_c.write("\t" + ret_ty_info.rust_obj + " ret;\n")
-                    out_c.write("\t(*env)->GetByteArrayRegion(env, jret, 0, " + ret_ty_info.arr_len + ", ret.data);\n")
-                    out_c.write("\treturn ret;\n")
-
-                if ret_ty_info.passed_as_ptr:
-                    out_c.write("\t" + fn_line.group(1).strip() + " res = *ret;\n")
-                    out_c.write("\tFREE(ret);\n")
-                    out_c.write("\treturn res;\n")
-                out_c.write("}\n")
-            elif fn_line.group(2) == "free":
-                out_c.write("static void " + struct_name + "_JCalls_free(void* this_arg) {\n")
-                out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
-                out_c.write("\tif (atomic_fetch_sub_explicit(&j_calls->refcnt, 1, memory_order_acquire) == 1) {\n")
-                out_c.write("\t\tJNIEnv *env;\n")
-                out_c.write("\t\tDO_ASSERT((*j_calls->vm)->GetEnv(j_calls->vm, (void**)&env, JNI_VERSION_1_8) == JNI_OK);\n")
-                out_c.write("\t\t(*env)->DeleteGlobalRef(env, j_calls->o);\n")
-                out_c.write("\t\tFREE(j_calls);\n")
-                out_c.write("\t}\n}\n")
-
-        # Write out a clone function whether we need one or not, as we use them in moving to rust
-        out_c.write("static void* " + struct_name + "_JCalls_clone(const void* this_arg) {\n")
-        out_c.write("\t" + struct_name + "_JCalls *j_calls = (" + struct_name + "_JCalls*) this_arg;\n")
-        out_c.write("\tatomic_fetch_add_explicit(&j_calls->refcnt, 1, memory_order_release);\n")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write("\tatomic_fetch_add_explicit(&j_calls->" + var_line.group(2) + "->refcnt, 1, memory_order_release);\n")
-        out_c.write("\treturn (void*) this_arg;\n")
-        out_c.write("}\n")
-
-        out_java.write("\t}\n")
-
-        out_java.write("\tpublic static native long " + struct_name + "_new(" + struct_name + " impl")
-        out_c.write("static inline " + struct_name + " " + struct_name + "_init (JNIEnv * env, jclass _a, jobject o")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_java.write(", " + var_line.group(1) + " " + var_line.group(2))
-                out_c.write(", jobject " + var_line.group(2))
-        out_java.write(");\n")
-        out_c.write(") {\n")
+            out_c.write("JNIEXPORT long JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new (JNIEnv * env, jclass _a, jobject o")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write(", jobject " + var_line.group(2))
+            out_c.write(") {\n")
+            out_c.write("\t" + struct_name + " *res_ptr = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")
+            out_c.write("\t*res_ptr = " + struct_name + "_init(env, _a, o")
+            for var_line in field_var_lines:
+                if var_line.group(1) in trait_structs:
+                    out_c.write(", " + var_line.group(2))
+            out_c.write(");\n")
+            out_c.write("\treturn (long)res_ptr;\n")
+            out_c.write("}\n")

 
 

-        out_c.write("\tjclass c = (*env)->GetObjectClass(env, o);\n")
-        out_c.write("\tDO_ASSERT(c != NULL);\n")
-        out_c.write("\t" + struct_name + "_JCalls *calls = MALLOC(sizeof(" + struct_name + "_JCalls), \"" + struct_name + "_JCalls\");\n")
-        out_c.write("\tatomic_init(&calls->refcnt, 1);\n")
-        out_c.write("\tDO_ASSERT((*env)->GetJavaVM(env, &calls->vm) == 0);\n")
-        out_c.write("\tcalls->o = (*env)->NewGlobalRef(env, o);\n")
-        for (fn_line, java_meth_descr) in zip(trait_fn_lines, java_meths):
-            if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
-                out_c.write("\tcalls->" + fn_line.group(2) + "_meth = (*env)->GetMethodID(env, c, \"" + fn_line.group(2) + "\", \"" + java_meth_descr + "\");\n")
-                out_c.write("\tDO_ASSERT(calls->" + fn_line.group(2) + "_meth != NULL);\n")
-        out_c.write("\n\t" + struct_name + " ret = {\n")
-        out_c.write("\t\t.this_arg = (void*) calls,\n")
-        for fn_line in trait_fn_lines:
-            if fn_line.group(2) != "free" and fn_line.group(2) != "clone":
-                out_c.write("\t\t." + fn_line.group(2) + " = " + fn_line.group(2) + "_jcall,\n")
-            elif fn_line.group(2) == "free":
-                out_c.write("\t\t.free = " + struct_name + "_JCalls_free,\n")
-            else:
-                out_c.write("\t\t.clone = " + struct_name + "_JCalls_clone,\n")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write("\t\t." + var_line.group(2) + " = " + var_line.group(1) + "_init(env, _a, " + var_line.group(2) + "),\n")
-        out_c.write("\t};\n")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write("\tcalls->" + var_line.group(2) + " = ret." + var_line.group(2) + ".this_arg;\n")
-        out_c.write("\treturn ret;\n")
-        out_c.write("}\n")
-
-        out_c.write("JNIEXPORT long JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new (JNIEnv * env, jclass _a, jobject o")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write(", jobject " + var_line.group(2))
-        out_c.write(") {\n")
-        out_c.write("\t" + struct_name + " *res_ptr = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")
-        out_c.write("\t*res_ptr = " + struct_name + "_init(env, _a, o")
-        for var_line in field_var_lines:
-            if var_line.group(1) in trait_structs:
-                out_c.write(", " + var_line.group(2))
-        out_c.write(");\n")
-        out_c.write("\treturn (long)res_ptr;\n")
-        out_c.write("}\n")
-
-        out_java.write("\tpublic static native " + struct_name + " " + struct_name + "_get_obj_from_jcalls(long val);\n")
-        out_c.write("JNIEXPORT jobject JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1get_1obj_1from_1jcalls (JNIEnv * env, jclass _a, jlong val) {\n")
-        out_c.write("\treturn ((" + struct_name + "_JCalls*)val)->o;\n")
-        out_c.write("}\n")
+            out_java.write("\tpublic static native " + struct_name + " " + struct_name + "_get_obj_from_jcalls(long val);\n")
+            out_c.write("JNIEXPORT jobject JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1get_1obj_1from_1jcalls (JNIEnv * env, jclass _a, jlong val) {\n")
+            out_c.write("\tjobject ret = (*env)->NewLocalRef(env, ((" + struct_name + "_JCalls*)val)->o);\n")
+            out_c.write("\tCHECK(ret != NULL);\n")
+            out_c.write("\treturn ret;\n")
+            out_c.write("}\n")

 
         for fn_line in trait_fn_lines:
             # For now, just disable enabling the _call_log - we don't know how to inverse-map String
             is_log = fn_line.group(2) == "log" and struct_name == "LDKLogger"
             if fn_line.group(2) != "free" and fn_line.group(2) != "clone" and fn_line.group(2) != "eq" and not is_log:
 
         for fn_line in trait_fn_lines:
             # For now, just disable enabling the _call_log - we don't know how to inverse-map String
             is_log = fn_line.group(2) == "log" and struct_name == "LDKLogger"
             if fn_line.group(2) != "free" and fn_line.group(2) != "clone" and fn_line.group(2) != "eq" and not is_log:

-                dummy_line = fn_line.group(1) + struct_name + "_call_" + fn_line.group(2) + " " + struct_name + "* arg" + fn_line.group(4) + "\n"
-                map_fn(dummy_line, re.compile("([A-Za-z_0-9]*) *([A-Za-z_0-9]*) *(.*)").match(dummy_line), None, "(arg_conv->" + fn_line.group(2) + ")(arg_conv->this_arg")
+                dummy_line = fn_line.group(1) + struct_name.replace("LDK", "") + "_" + fn_line.group(2) + " " + struct_name + "* this_arg" + fn_line.group(4) + "\n"
+                map_fn(dummy_line, re.compile("([A-Za-z_0-9]*) *([A-Za-z_0-9]*) *(.*)").match(dummy_line), None, "(this_arg_conv->" + fn_line.group(2) + ")(this_arg_conv->this_arg")

 
     out_c.write("""#include \"org_ldk_impl_bindings.h\"
 #include <rust_types.h>
 
     out_c.write("""#include \"org_ldk_impl_bindings.h\"
 #include <rust_types.h>


@@ -665,11 +1213,15 @@ with open(sys.argv[1]) as in_h, open(sys.argv[2], "w") as out_java, open(sys.arg
 
     if sys.argv[4] == "false":
         out_c.write("#define MALLOC(a, _) malloc(a)\n")
 
     if sys.argv[4] == "false":
         out_c.write("#define MALLOC(a, _) malloc(a)\n")

-        out_c.write("#define FREE free\n")
+        out_c.write("#define FREE(p) if ((p) > 1024) { free(p); }\n")

         out_c.write("#define DO_ASSERT(a) (void)(a)\n")
         out_c.write("#define DO_ASSERT(a) (void)(a)\n")

+        out_c.write("#define CHECK(a)\n")

     else:
         out_c.write("""#include <assert.h>
     else:
         out_c.write("""#include <assert.h>

+// Always run a, then assert it is true:

 #define DO_ASSERT(a) do { bool _assert_val = (a); assert(_assert_val); } while(0)
 #define DO_ASSERT(a) do { bool _assert_val = (a); assert(_assert_val); } while(0)

+// Assert a is true or do nothing
+#define CHECK(a) DO_ASSERT(a)

 
 // Running a leak check across all the allocations and frees of the JDK is a mess,
 // so instead we implement our own naive leak checker here, relying on the -wrap
 
 // Running a leak check across all the allocations and frees of the JDK is a mess,
 // so instead we implement our own naive leak checker here, relying on the -wrap


@@ -723,6 +1275,7 @@ static void alloc_freed(void* ptr) {
        __real_free(it);
 }
 static void FREE(void* ptr) {
        __real_free(it);
 }
 static void FREE(void* ptr) {

+       if ((long)ptr < 1024) return; // Rust loves to create pointers to the NULL page for dummys

        alloc_freed(ptr);
        __real_free(ptr);
 }
        alloc_freed(ptr);
        __real_free(ptr);
 }


@@ -798,11 +1351,11 @@ static jmethodID slicedef_meth = NULL;
 static jclass slicedef_cls = NULL;
 JNIEXPORT void Java_org_ldk_impl_bindings_init(JNIEnv * env, jclass _b, jclass enum_class, jclass slicedef_class) {
        ordinal_meth = (*env)->GetMethodID(env, enum_class, "ordinal", "()I");
 static jclass slicedef_cls = NULL;
 JNIEXPORT void Java_org_ldk_impl_bindings_init(JNIEnv * env, jclass _b, jclass enum_class, jclass slicedef_class) {
        ordinal_meth = (*env)->GetMethodID(env, enum_class, "ordinal", "()I");

-       DO_ASSERT(ordinal_meth != NULL);
+       CHECK(ordinal_meth != NULL);

        slicedef_meth = (*env)->GetMethodID(env, slicedef_class, "<init>", "(JJJ)V");
        slicedef_meth = (*env)->GetMethodID(env, slicedef_class, "<init>", "(JJJ)V");

-       DO_ASSERT(slicedef_meth != NULL);
+       CHECK(slicedef_meth != NULL);

        slicedef_cls = (*env)->NewGlobalRef(env, slicedef_class);
        slicedef_cls = (*env)->NewGlobalRef(env, slicedef_class);

-       DO_ASSERT(slicedef_cls != NULL);
+       CHECK(slicedef_cls != NULL);

 }
 
 JNIEXPORT jboolean JNICALL Java_org_ldk_impl_bindings_deref_1bool (JNIEnv * env, jclass _a, jlong ptr) {
 }
 
 JNIEXPORT jboolean JNICALL Java_org_ldk_impl_bindings_deref_1bool (JNIEnv * env, jclass _a, jlong ptr) {


@@ -868,22 +1421,23 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
 
 """)
 
 
 """)
 

-    # XXX: Temporarily write out a manual SecretKey_new() for testing, we should auto-gen this kind of thing
-    out_java.write("\tpublic static native long LDKSecretKey_new();\n\n") # TODO: rm me
-    out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_LDKSecretKey_1new(JNIEnv * _env, jclass _b) {\n") # TODO: rm me
-    out_c.write("\tLDKSecretKey* key = (LDKSecretKey*)MALLOC(sizeof(LDKSecretKey), \"LDKSecretKey\");\n") # TODO: rm me
-    out_c.write("\treturn (long)key;\n") # TODO: rm me
-    out_c.write("}\n") # TODO: rm me
+    with open(sys.argv[3] + "/structs/CommonBase.java", "a") as out_java_struct:
+        out_java_struct.write("""package org.ldk.structs;
+import java.util.LinkedList;
+class CommonBase {
+       final long ptr;
+       LinkedList<Object> ptrs_to = new LinkedList();
+       protected CommonBase(long ptr) { this.ptr = ptr; }
+       public long _test_only_get_ptr() { return this.ptr; }
+}
+""")

 
     in_block_comment = False
     cur_block_obj = None
 
 
     in_block_comment = False
     cur_block_obj = None
 

-    fn_ptr_regex = re.compile("^extern const ([A-Za-z_0-9\* ]*) \(\*(.*)\)\((.*)\);$")
-    fn_ret_arr_regex = re.compile("(.*) \(\*(.*)\((.*)\)\)\[([0-9]*)\];$")
-    reg_fn_regex = re.compile("([A-Za-z_0-9\* ]* \*?)([a-zA-Z_0-9]*)\((.*)\);$")

     const_val_regex = re.compile("^extern const ([A-Za-z_0-9]*) ([A-Za-z_0-9]*);$")
 
     const_val_regex = re.compile("^extern const ([A-Za-z_0-9]*) ([A-Za-z_0-9]*);$")
 

-    line_indicates_result_regex = re.compile("^   bool result_ok;$")
+    line_indicates_result_regex = re.compile("^   (LDKCResultPtr_[A-Za-z_0-9]*) contents;$")

     line_indicates_vec_regex = re.compile("^   ([A-Za-z_0-9]*) \*data;$")
     line_indicates_opaque_regex = re.compile("^   bool is_owned;$")
     line_indicates_trait_regex = re.compile("^   ([A-Za-z_0-9]* \*?)\(\*([A-Za-z_0-9]*)\)\((const )?void \*this_arg(.*)\);$")
     line_indicates_vec_regex = re.compile("^   ([A-Za-z_0-9]*) \*data;$")
     line_indicates_opaque_regex = re.compile("^   bool is_owned;$")
     line_indicates_trait_regex = re.compile("^   ([A-Za-z_0-9]* \*?)\(\*([A-Za-z_0-9]*)\)\((const )?void \*this_arg(.*)\);$")


@@ -900,6 +1454,7 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
 
     result_templ_structs = set()
     union_enum_items = {}
 
     result_templ_structs = set()
     union_enum_items = {}

+    result_ptr_struct_items = {}

     for line in in_h:
         if in_block_comment:
             if line.endswith("*/\n"):
     for line in in_h:
         if in_block_comment:
             if line.endswith("*/\n"):


@@ -912,7 +1467,7 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                 vec_ty = None
                 obj_lines = cur_block_obj.split("\n")
                 is_opaque = False
                 vec_ty = None
                 obj_lines = cur_block_obj.split("\n")
                 is_opaque = False

-                is_result = False
+                result_contents = None

                 is_unitary_enum = False
                 is_union_enum = False
                 is_union = False
                 is_unitary_enum = False
                 is_union_enum = False
                 is_union = False


@@ -939,8 +1494,9 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                                 is_union = True
                         if line_indicates_opaque_regex.match(struct_line):
                             is_opaque = True
                                 is_union = True
                         if line_indicates_opaque_regex.match(struct_line):
                             is_opaque = True

-                        elif line_indicates_result_regex.match(struct_line):
-                            is_result = True
+                        result_match = line_indicates_result_regex.match(struct_line)
+                        if result_match is not None:
+                            result_contents = result_match.group(1)

                         vec_ty_match = line_indicates_vec_regex.match(struct_line)
                         if vec_ty_match is not None and struct_name.startswith("LDKCVecTempl_"):
                             vec_ty = vec_ty_match.group(1)
                         vec_ty_match = line_indicates_vec_regex.match(struct_line)
                         if vec_ty_match is not None and struct_name.startswith("LDKCVecTempl_"):
                             vec_ty = vec_ty_match.group(1)


@@ -955,21 +1511,45 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                         field_lines.append(struct_line)
 
                 assert(struct_name is not None)
                         field_lines.append(struct_line)
 
                 assert(struct_name is not None)

-                assert(len(trait_fn_lines) == 0 or not (is_opaque or is_unitary_enum or is_union_enum or is_union or is_result or vec_ty is not None))
-                assert(not is_opaque or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_union or is_result or vec_ty is not None))
-                assert(not is_unitary_enum or not (len(trait_fn_lines) != 0 or is_opaque or is_union_enum or is_union or is_result or vec_ty is not None))
-                assert(not is_union_enum or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_opaque or is_union or is_result or vec_ty is not None))
-                assert(not is_union or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or is_result or vec_ty is not None))
-                assert(not is_result or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or is_union or vec_ty is not None))
-                assert(vec_ty is None or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or is_union or is_result))
+                assert(len(trait_fn_lines) == 0 or not (is_opaque or is_unitary_enum or is_union_enum or is_union or result_contents is not None or vec_ty is not None))
+                assert(not is_opaque or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_union or result_contents is not None or vec_ty is not None))
+                assert(not is_unitary_enum or not (len(trait_fn_lines) != 0 or is_opaque or is_union_enum or is_union or result_contents is not None or vec_ty is not None))
+                assert(not is_union_enum or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_opaque or is_union or result_contents is not None or vec_ty is not None))
+                assert(not is_union or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or result_contents is not None or vec_ty is not None))
+                assert(result_contents is None or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or is_union or vec_ty is not None))
+                assert(vec_ty is None or not (len(trait_fn_lines) != 0 or is_unitary_enum or is_union_enum or is_opaque or is_union or result_contents is not None))

 
                 if is_opaque:
                     opaque_structs.add(struct_name)
 
                 if is_opaque:
                     opaque_structs.add(struct_name)

-                elif is_result:
+                    with open(sys.argv[3] + "/structs/" + struct_name.replace("LDK","") + ".java", "w") as out_java_struct:
+                        out_java_struct.write(hu_struct_file_prefix)
+                        out_java_struct.write("public class " + struct_name.replace("LDK","") + " extends CommonBase")
+                        if struct_name.startswith("LDKLocked"):
+                            out_java_struct.write(" implements AutoCloseable")
+                        out_java_struct.write(" {\n")
+                        out_java_struct.write("\t" + struct_name.replace("LDK", "") + "(Object _dummy, long ptr) { super(ptr); }\n")
+                        if struct_name.startswith("LDKLocked"):
+                            out_java_struct.write("\t@Override public void close() {\n")
+                        else:
+                            out_java_struct.write("\t@Override @SuppressWarnings(\"deprecation\")\n")
+                            out_java_struct.write("\tprotected void finalize() throws Throwable {\n")
+                            out_java_struct.write("\t\tsuper.finalize();\n")
+                        out_java_struct.write("\t\tbindings." + struct_name.replace("LDK","") + "_free(ptr);\n")
+                        out_java_struct.write("\t}\n\n")
+                elif result_contents is not None:

                     result_templ_structs.add(struct_name)
                     result_templ_structs.add(struct_name)

+                    assert result_contents in result_ptr_struct_items
+                elif struct_name.startswith("LDKCResultPtr_"):
+                    for line in field_lines:
+                        if line.endswith("*result;"):
+                            res_ty = line[:-8].strip()
+                        elif line.endswith("*err;"):
+                            err_ty = line[:-5].strip()
+                    result_ptr_struct_items[struct_name] = (res_ty, err_ty)

                 elif is_tuple:
                     out_java.write("\tpublic static native long " + struct_name + "_new(")
                     out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new(JNIEnv *_env, jclass _b")
                 elif is_tuple:
                     out_java.write("\tpublic static native long " + struct_name + "_new(")
                     out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new(JNIEnv *_env, jclass _b")

+                    ty_list = []

                     for idx, line in enumerate(field_lines):
                         if idx != 0 and idx < len(field_lines) - 2:
                             ty_info = java_c_types(line.strip(';'), None)
                     for idx, line in enumerate(field_lines):
                         if idx != 0 and idx < len(field_lines) - 2:
                             ty_info = java_c_types(line.strip(';'), None)


@@ -978,6 +1558,8 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                             e = chr(ord('a') + idx - 1)
                             out_java.write(ty_info.java_ty + " " + e)
                             out_c.write(", " + ty_info.c_ty + " " + e)
                             e = chr(ord('a') + idx - 1)
                             out_java.write(ty_info.java_ty + " " + e)
                             out_c.write(", " + ty_info.c_ty + " " + e)

+                            ty_list.append(ty_info)
+                    tuple_types[struct_name] = (ty_list, struct_name)

                     out_java.write(");\n")
                     out_c.write(") {\n")
                     out_c.write("\t" + struct_name + "* ret = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")
                     out_java.write(");\n")
                     out_c.write(") {\n")
                     out_c.write("\t" + struct_name + "* ret = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")


@@ -990,6 +1572,8 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                                 out_c.write("\n\tret->" + e + " = " + ty_info.arg_conv_name + ";\n")
                             else:
                                 out_c.write("\tret->" + e + " = " + e + ";\n")
                                 out_c.write("\n\tret->" + e + " = " + ty_info.arg_conv_name + ";\n")
                             else:
                                 out_c.write("\tret->" + e + " = " + e + ";\n")

+                            if ty_info.arg_conv_cleanup is not None:
+                                out_c.write("\t//TODO: Really need to call " + ty_info.arg_conv_cleanup + " here\n")

                     out_c.write("\treturn (long)ret;\n")
                     out_c.write("}\n")
                 elif vec_ty is not None:
                     out_c.write("\treturn (long)ret;\n")
                     out_c.write("}\n")
                 elif vec_ty is not None:


@@ -1004,7 +1588,7 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                         out_c.write("\tjlongArray ret = (*env)->NewLongArray(env, vec->datalen);\n")
                         out_c.write("\tjlong *ret_elems = (*env)->GetPrimitiveArrayCritical(env, ret, NULL);\n")
                         out_c.write("\tfor (size_t i = 0; i < vec->datalen; i++) {\n")
                         out_c.write("\tjlongArray ret = (*env)->NewLongArray(env, vec->datalen);\n")
                         out_c.write("\tjlong *ret_elems = (*env)->GetPrimitiveArrayCritical(env, ret, NULL);\n")
                         out_c.write("\tfor (size_t i = 0; i < vec->datalen; i++) {\n")

-                        out_c.write("\t\tDO_ASSERT((((long)vec->data[i].inner) & 1) == 0);\n")
+                        out_c.write("\t\tCHECK((((long)vec->data[i].inner) & 1) == 0);\n")

                         out_c.write("\t\tret_elems[i] = (long)vec->data[i].inner | (vec->data[i].is_owned ? 1 : 0);\n")
                         out_c.write("\t}\n")
                         out_c.write("\t(*env)->ReleasePrimitiveArrayCritical(env, ret, ret_elems, 0);\n")
                         out_c.write("\t\tret_elems[i] = (long)vec->data[i].inner | (vec->data[i].is_owned ? 1 : 0);\n")
                         out_c.write("\t}\n")
                         out_c.write("\t(*env)->ReleasePrimitiveArrayCritical(env, ret, ret_elems, 0);\n")


@@ -1014,28 +1598,29 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                     out_c.write("}\n")
 
                     ty_info = map_type(vec_ty + " arr_elem", False, None, False)
                     out_c.write("}\n")
 
                     ty_info = map_type(vec_ty + " arr_elem", False, None, False)

-                    out_java.write("\tpublic static native long " + struct_name + "_new(" + ty_info.java_ty + "[] elems);\n")
-                    out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new(JNIEnv *env, jclass _b, j" + ty_info.java_ty + "Array elems){\n")
-                    out_c.write("\t" + struct_name + " *ret = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")
-                    out_c.write("\tret->datalen = (*env)->GetArrayLength(env, elems);\n")
-                    out_c.write("\tif (ret->datalen == 0) {\n")
-                    out_c.write("\t\tret->data = NULL;\n")
-                    out_c.write("\t} else {\n")
-                    out_c.write("\t\tret->data = MALLOC(sizeof(" + vec_ty + ") * ret->datalen, \"" + struct_name + " Data\");\n")
-                    assert len(ty_info.java_fn_ty_arg) == 1 # ie we're a primitive of some form
-                    out_c.write("\t\t" + ty_info.c_ty + " *java_elems = (*env)->GetPrimitiveArrayCritical(env, elems, NULL);\n")
-                    out_c.write("\t\tfor (size_t i = 0; i < ret->datalen; i++) {\n")
-                    if ty_info.arg_conv is not None:
-                        out_c.write("\t\t\t" + ty_info.c_ty + " arr_elem = java_elems[i];\n")
-                        out_c.write("\t\t\t" + ty_info.arg_conv.replace("\n", "\n\t\t\t") + "\n")
-                        out_c.write("\t\t\tret->data[i] = " + ty_info.arg_conv_name + ";\n")
-                    else:
-                        out_c.write("\t\t\tret->data[i] = java_elems[i];\n")
-                    out_c.write("\t\t}\n")
-                    out_c.write("\t\t(*env)->ReleasePrimitiveArrayCritical(env, elems, java_elems, 0);\n")
-                    out_c.write("\t}\n")
-                    out_c.write("\treturn (long)ret;\n")
-                    out_c.write("}\n")
+                    if len(ty_info.java_fn_ty_arg) == 1: # ie we're a primitive of some form
+                        out_java.write("\tpublic static native long " + struct_name + "_new(" + ty_info.java_ty + "[] elems);\n")
+                        out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_" + struct_name.replace("_", "_1") + "_1new(JNIEnv *env, jclass _b, j" + ty_info.java_ty + "Array elems){\n")
+                        out_c.write("\t" + struct_name + " *ret = MALLOC(sizeof(" + struct_name + "), \"" + struct_name + "\");\n")
+                        out_c.write("\tret->datalen = (*env)->GetArrayLength(env, elems);\n")
+                        out_c.write("\tif (ret->datalen == 0) {\n")
+                        out_c.write("\t\tret->data = NULL;\n")
+                        out_c.write("\t} else {\n")
+                        out_c.write("\t\tret->data = MALLOC(sizeof(" + vec_ty + ") * ret->datalen, \"" + struct_name + " Data\");\n")
+                        out_c.write("\t\t" + ty_info.c_ty + " *java_elems = (*env)->GetPrimitiveArrayCritical(env, elems, NULL);\n")
+                        out_c.write("\t\tfor (size_t i = 0; i < ret->datalen; i++) {\n")
+                        if ty_info.arg_conv is not None:
+                            out_c.write("\t\t\t" + ty_info.c_ty + " arr_elem = java_elems[i];\n")
+                            out_c.write("\t\t\t" + ty_info.arg_conv.replace("\n", "\n\t\t\t") + "\n")
+                            out_c.write("\t\t\tret->data[i] = " + ty_info.arg_conv_name + ";\n")
+                            assert ty_info.arg_conv_cleanup is None
+                        else:
+                            out_c.write("\t\t\tret->data[i] = java_elems[i];\n")
+                        out_c.write("\t\t}\n")
+                        out_c.write("\t\t(*env)->ReleasePrimitiveArrayCritical(env, elems, java_elems, 0);\n")
+                        out_c.write("\t}\n")
+                        out_c.write("\treturn (long)ret;\n")
+                        out_c.write("}\n")

                 elif is_union_enum:
                     assert(struct_name.endswith("_Tag"))
                     struct_name = struct_name[:-4]
                 elif is_union_enum:
                     assert(struct_name.endswith("_Tag"))
                     struct_name = struct_name[:-4]


@@ -1050,6 +1635,22 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                 elif len(trait_fn_lines) > 0:
                     trait_structs.add(struct_name)
                     map_trait(struct_name, field_var_lines, trait_fn_lines)
                 elif len(trait_fn_lines) > 0:
                     trait_structs.add(struct_name)
                     map_trait(struct_name, field_var_lines, trait_fn_lines)

+                elif struct_name == "LDKTxOut":
+                    with open(sys.argv[3] + "/structs/TxOut.java", "w") as out_java_struct:
+                        out_java_struct.write(hu_struct_file_prefix)
+                        out_java_struct.write("public class TxOut extends CommonBase{\n")
+                        out_java_struct.write("\tTxOut(java.lang.Object _dummy, long ptr) { super(ptr); }\n")
+                        # TODO: TxOut body
+                        out_java_struct.write("}")
+                elif struct_name == "LDKTransaction":
+                    with open(sys.argv[3] + "/structs/Transaction.java", "w") as out_java_struct:
+                        out_java_struct.write(hu_struct_file_prefix)
+                        out_java_struct.write("public class Transaction extends CommonBase{\n")
+                        out_java_struct.write("\tTransaction(java.lang.Object _dummy, long ptr) { super(ptr); }\n")
+                        # TODO: Transaction body
+                        out_java_struct.write("}")
+                else:
+                    pass # Everything remaining is a byte[] or some form

                 cur_block_obj = None
         else:
             fn_ptr = fn_ptr_regex.match(line)
                 cur_block_obj = None
         else:
             fn_ptr = fn_ptr_regex.match(line)


@@ -1071,19 +1672,78 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                 cur_block_obj = line
             elif line.startswith("typedef "):
                 alias_match =  struct_alias_regex.match(line)
                 cur_block_obj = line
             elif line.startswith("typedef "):
                 alias_match =  struct_alias_regex.match(line)

-                if alias_match.group(1) in result_templ_structs:
-                    out_java.write("\tpublic static native boolean " + alias_match.group(2) + "_result_ok(long arg);\n")
-                    out_java.write("\tpublic static native long " + alias_match.group(2) + "_get_inner(long arg);\n")
-                    out_c.write("JNIEXPORT jboolean JNICALL Java_org_ldk_impl_bindings_" + alias_match.group(2).replace("_", "_1") + "_1result_1ok (JNIEnv * env, jclass _a, jlong arg) {\n")
-                    out_c.write("\treturn ((" + alias_match.group(2) + "*)arg)->result_ok;\n")
-                    out_c.write("}\n")
-                    out_c.write("JNIEXPORT jlong JNICALL Java_org_ldk_impl_bindings_" + alias_match.group(2).replace("_", "_1") + "_1get_1inner (JNIEnv * env, jclass _a, jlong arg) {\n")
-                    out_c.write("\tif (((" + alias_match.group(2) + "*)arg)->result_ok) {\n")
-                    out_c.write("\t\treturn (long)((" + alias_match.group(2) + "*)arg)->contents.result;\n")
-                    out_c.write("\t} else {\n")
-                    out_c.write("\t\treturn (long)((" + alias_match.group(2) + "*)arg)->contents.err;\n")
-                    out_c.write("\t}\n}\n")
-                pass
+                if alias_match.group(1) in tuple_types:
+                    tuple_types[alias_match.group(2)] = (tuple_types[alias_match.group(1)][0], alias_match.group(2))
+                    tuple_types[alias_match.group(1)] = (tuple_types[alias_match.group(1)][0], alias_match.group(2))
+                    for idx, ty_info in enumerate(tuple_types[alias_match.group(1)][0]):
+                        e = chr(ord('a') + idx)
+                        out_java.write("\tpublic static native " + ty_info.java_ty + " " + alias_match.group(2) + "_get_" + e + "(long ptr);\n")
+                        # XXX: Write C method!
+                elif alias_match.group(1) in result_templ_structs:
+                    human_ty = alias_match.group(2).replace("LDKCResult", "Result_").replace("__", "_").replace("Templ", "")
+                    with open(sys.argv[3] + "/structs/" + human_ty + ".java", "w") as out_java_struct:
+                        out_java_struct.write(hu_struct_file_prefix)
+                        out_java_struct.write("public class " + human_ty + " extends CommonBase {\n")
+                        out_java_struct.write("\tprivate " + human_ty + "(Object _dummy, long ptr) { super(ptr); }\n")
+                        out_java_struct.write("\tprotected void finalize() throws Throwable {\n")
+                        out_java_struct.write("\t\tbindings." + alias_match.group(2).replace("LDK","") + "_free(ptr); super.finalize();\n")
+                        out_java_struct.write("\t}\n\n")
+
+                        contents_ty = alias_match.group(1).replace("LDKCResultTempl", "LDKCResultPtr")
+                        res_ty, err_ty = result_ptr_struct_items[contents_ty]
+                        res_map = map_type(res_ty + " res", True, None, False)
+                        err_map = map_type(err_ty + " err", True, None, False)
+
+                        out_java.write("\tpublic static native boolean " + alias_match.group(2) + "_result_ok(long arg);\n")
+                        out_c.write("JNIEXPORT jboolean JNICALL Java_org_ldk_impl_bindings_" + alias_match.group(2).replace("_", "_1") + "_1result_1ok (JNIEnv * env, jclass _a, jlong arg) {\n")
+                        out_c.write("\treturn ((" + alias_match.group(2) + "*)arg)->result_ok;\n")
+                        out_c.write("}\n")
+
+                        out_java.write("\tpublic static native " + res_map.java_ty + " " + alias_match.group(2) + "_get_ok(long arg);\n")
+                        out_c.write("JNIEXPORT " + res_map.c_ty + " JNICALL Java_org_ldk_impl_bindings_" + alias_match.group(2).replace("_", "_1") + "_1get_1ok (JNIEnv * _env, jclass _a, jlong arg) {\n")
+                        out_c.write("\t" + alias_match.group(2) + " *val = (" + alias_match.group(2) + "*)arg;\n")
+                        out_c.write("\tCHECK(val->result_ok);\n\t")
+                        out_java_struct.write("\tpublic static final class " + human_ty + "_OK extends " + human_ty + " {\n")
+                        if res_map.ret_conv is not None:
+                            out_c.write(res_map.ret_conv[0].replace("\n", "\n\t") + "(*val->contents.result)")
+                            out_c.write(res_map.ret_conv[1].replace("\n", "\n\t") + "\n\treturn " + res_map.ret_conv_name)
+                        else:
+                            out_c.write("return *val->contents.result")
+                        out_c.write(";\n}\n")
+
+                        out_java_struct.write("\t\tpublic " + res_map.java_hu_ty + " res;\n")
+                        out_java_struct.write("\t\tprivate " + human_ty + "_OK(Object _dummy, long ptr) {\n")
+                        out_java_struct.write("\t\t\tsuper(_dummy, ptr);\n")
+                        if res_map.to_hu_conv is not None:
+                            out_java_struct.write("\t\t\t" + res_map.java_ty + " res = bindings." + alias_match.group(2) + "_get_ok(ptr);\n")
+                            out_java_struct.write("\t\t\t" + res_map.to_hu_conv.replace("\n", "\n\t\t\t"))
+                            out_java_struct.write("\n\t\t\tthis.res = " + res_map.to_hu_conv_name + ";\n")
+                        else:
+                            out_java_struct.write("\t\t\tthis.res = bindings." + alias_match.group(2) + "_get_ok(ptr);\n")
+                        out_java_struct.write("\t\t}\n\n")
+
+                        out_java.write("\tpublic static native " + err_map.java_ty + " " + alias_match.group(2) + "_get_err(long arg);\n")
+                        out_c.write("JNIEXPORT " + err_map.c_ty + " JNICALL Java_org_ldk_impl_bindings_" + alias_match.group(2).replace("_", "_1") + "_1get_1err (JNIEnv * _env, jclass _a, jlong arg) {\n")
+                        out_c.write("\t" + alias_match.group(2) + " *val = (" + alias_match.group(2) + "*)arg;\n")
+                        out_c.write("\tCHECK(!val->result_ok);\n\t")
+                        out_java_struct.write("\t}\n\tpublic static final class " + human_ty + "_Err extends " + human_ty + " {\n")
+                        if err_map.ret_conv is not None:
+                            out_c.write(err_map.ret_conv[0].replace("\n", "\n\t") + "(*val->contents.err)")
+                            out_c.write(err_map.ret_conv[1].replace("\n", "\n\t") + "\n\treturn " + err_map.ret_conv_name)
+                        else:
+                            out_c.write("return *val->contents.err")
+                        out_c.write(";\n}\n")
+
+                        out_java_struct.write("\t\tpublic " + err_map.java_hu_ty + " err;\n")
+                        out_java_struct.write("\t\tprivate " + human_ty + "_Err(Object _dummy, long ptr) {\n")
+                        out_java_struct.write("\t\t\tsuper(_dummy, ptr);\n")
+                        if err_map.to_hu_conv is not None:
+                            out_java_struct.write("\t\t\t" + err_map.java_ty + " err = bindings." + alias_match.group(2) + "_get_err(ptr);\n")
+                            out_java_struct.write("\t\t\t" + err_map.to_hu_conv.replace("\n", "\n\t\t\t"))
+                            out_java_struct.write("\n\t\t\tthis.err = " + err_map.to_hu_conv_name + ";\n")
+                        else:
+                            out_java_struct.write("\t\t\tthis.err = bindings." + alias_match.group(2) + "_get_err(ptr);\n")
+                        out_java_struct.write("\t\t}\n\t}\n}\n")

             elif fn_ptr is not None:
                 map_fn(line, fn_ptr, None, None)
             elif fn_ret_arr is not None:
             elif fn_ptr is not None:
                 map_fn(line, fn_ptr, None, None)
             elif fn_ret_arr is not None:


@@ -1097,3 +1757,9 @@ _Static_assert(offsetof(LDKCVec_u8Z, datalen) == offsetof(LDKu8slice, datalen),
                 assert(line == "\n")
 
     out_java.write("}\n")
                 assert(line == "\n")
 
     out_java.write("}\n")

+    for struct_name in opaque_structs:
+        with open(sys.argv[3] + "/structs/" + struct_name.replace("LDK","") + ".java", "a") as out_java_struct:
+            out_java_struct.write("}\n")
+    for struct_name in trait_structs:
+        with open(sys.argv[3] + "/structs/" + struct_name.replace("LDK","") + ".java", "a") as out_java_struct:
+            out_java_struct.write("}\n")