question: private void cleanupAll ( ) { T current ; while ( ( current = objects . poll ( ) ) != null ) cleanup ( current ) ; }
target:  Invokes the cleanup() function on all tracked objects, removing each object from the underlying collection. It is guaranteed that cleanup() will be invoked only once for each object, even if multiple calls to cleanupAll() are running concurrently, and that the underlying collection will be empty after all calls to cleanupAll() complete.