Java JNI return map

extern "C"
jobject
java_com_example_admin_testusecpp_mainactivity_retmap (
        jnienv* env,
        jobject/* This */) {
    Jclass java_cls_hashmap = Env->findclass ("Java/util/hashmap");
    Jmethodid Java_mid_hashmap = Env->getmethodid (Java_cls_hashmap, "<init>", "() V");
    Jobject  java_obj_hashmap = Env->newobject (Java_cls_hashmap, Java_mid_hashmap, "");
    Jmethodid java_mid_hashmap_put = Env->getmethodid (Java_cls_hashmap, "put", "(Ljava/lang/object; Ljava/lang/object;) ljava/lang/object; ");
    Env->callobjectmethod (Java_obj_hashmap, Java_mid_hashmap_put, Env->newstringutf ("key"), env-> Newstringutf ("value"));
    return java_obj_hashmap;
}