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• ObjC objects that are +alloc'd or -retained are not actually pinned in GC-mode unless they have been CFRetain()'d
  • As a counterpoint, any CFRetain()'d ObjC object must be -released or -autoreleased for it's retain count to remain balanced in RR mode
• The ObjC garbage collector cannot see into the Java heap, and infer if any native objects are still "alive"

Don't manage JNI global refs yourself

• If you need to pass a Java object through native (like to the main AppKit thread, or inside of an NSArray), use JNFJObjectWrapper or JNFJObjectWeakWrapper
  • It handles all the details of managing a JNI global ref in a native ObjC object in both RR and GC modes
• If you have a JNIEnv when you are done with the JNFJObjectWrapper, pre-clear the reference
  • It is more efficient than the wrapper's -dealloc, which may have to connect the current thread to the JVM (possibly a ObjC-GC collector thread), just for the purposes of deleting the ref.