The macOS implementation of awt_CreateEmbeddedFrame incorrectly caches a local reference to the embedded frame class, resulting in a crash if invoked a second time.

JNIEXPORT jobject JNICALL awt_CreateEmbeddedFrame
(JNIEnv* env, void* platformInfo)
{
    static jmethodID mid = NULL;
    static jclass cls;
    if (mid == NULL) {
        cls = (*env)->FindClass(env, embeddedClassName);
        CHECK_NULL_RETURN(cls, NULL);
        mid = (*env)->GetMethodID(env, cls, "<init>", "(J)V");
        CHECK_NULL_RETURN(mid, NULL);
    }
    return (*env)->NewObject(env, cls, mid, platformInfo);
}