redef fun compile_callback_to_java(mmodule, mainmodule, ccu)
	do
		if not mmodule.callbacks_used_from_java.callbacks.has(self) then return

		var mproperty = mproperty
		assert mproperty isa MMethod

		# In C, indirection implementing the Java extern methods
		var csignature = mproperty.build_c_implementation_signature(recv_mtype, mmodule, "___indirect", long_signature, from_java_call_context)
		var cf = new CFunction("JNIEXPORT {csignature}")
		cf.exprs.add "\t{mproperty.build_ccall(recv_mtype, mainmodule, null, long_signature, from_java_call_context, null)}\n"
		ccu.add_non_static_local_function cf

		# In Java, declare the extern method as a private static local method
		var java_signature = mproperty.build_csignature(recv_mtype, mainmodule, null, short_signature, java_call_context)
		mmodule.java_file.class_content.add "private native static {java_signature};\n"
	end

	redef fun compile_callback_to_java(mmodule, mainmodule, ccu)
	do
		if self isa MClassType and mclass.ftype isa ForeignJavaType then return

		var java_file = mmodule.java_file
		if java_file == null or mmodule.callbacks_used_from_java.callbacks.is_empty then return

		for variation in ["incr", "decr"] do
			var friendly_name = "{mangled_cname}_{variation}_ref"

			# C
			var csignature = "void {mmodule.impl_java_class_name}_{friendly_name}(JNIEnv *nit_ffi_jni_env, jclass clazz, jobject object)"
			var cf = new CFunction("JNIEXPORT {csignature}")
			cf.exprs.add "\tnitni_global_ref_{variation}(nit_ffi_with_java_nit_object_data(nit_ffi_jni_env, object));"
			ccu.add_non_static_local_function cf

			# Java
			java_file.class_content.add "private native static void {friendly_name}(nit.app.NitObject object);\n"
		end
	end

	redef fun compile_callback_to_java(mmodule, mainmodule, ccu)
	do
		# Don't generate functions for reference counters on extern classes
		if mclass.ftype != null then return

		super
	end