class_descriptor->java_class = NULL;
enumerate_remove_java_class(JSJHashEntry *he, PRIntn i, void *arg){    JNIEnv *jEnv = (JNIEnv*)arg;    jclass java_class;    java_class = (jclass)he->key;    (*jEnv)->DeleteGlobalRef(jEnv, java_class);    return HT_ENUMERATE_REMOVE;}