JNI: marking and unmarking global and local references

Sun Mar 25 17:42:00 GMT 2001

JNI says that local and global references are different categories,
but the mark_for_gc and unmark_for_gc conflate them. For example, the
GCJ libjava runtime will undo the intent of the NewGlobalRef below
(create a unique handle to a preserved global object), since gref and
lref end up having the same value.
 jobject lref = (*env)->GetObjectClass (env, obj);
 jobject gref = (*env)->NewGlobalRef (env, lref);
 (*env)->DeleteLocalRef (env, lref)