BridgeUtils.cpp should be rewritten to make use of wrappers instead of raw JNI objects. E.g.
    JLObject valClass(JSC::Bindings::callJNIMethod<jobject>(val, "getClass", "()Ljava/lang/Class;"));
instead of
    jobject valClass = JSC::Bindings::callJNIMethod<jobject>(val, "getClass", "()Ljava/lang/Class;");