JNIEXPORT jobject JNICALL
JNU_NewObjectByName(JNIEnv *env, const char *class_name, const char *constructor_sig, ...)
{
    jobject obj = NULL;
    jclass cls = 0;
    jmethodID cls_initMID;
    va_list args;

    if((*env)->EnsureLocalCapacity(env, 2) < 0) {
        goto done;
    }

    cls = (*env)->FindClass(env, class_name);
    if(cls == 0) goto done;

    cls_initMID = (*env)->GetMethodID(env, cls, "<init>", constructor_sig);
    if (cls_initMID == NULL) goto done;

    va_start(args, constructor_sig);
    obj = (*env)->NewObjectV(env, cls, cls_initMID, args);
    va_end(args);

 done:
    (*env)->DeleteLocalRef(env, cls);
    return obj;
}