Concurrentmodificationexception and a HashMap

This is a synchronization problem. This'll occur if the underlying collection that's being iterated over are modified by anything other than the Iterator I Tself.

Iterator it = map.entryset (). Iterator ();  while (It.hasnext ()) {   = it.next ();   Map.Remove (Item.getkey ());}

This would throw a concurrentmodificationexception when the It.hasnext () is called the second time.

The correct approach would be

   Iterator it = map.entryset (). Iterator ();     while (It.hasnext ())   {      = it.next ();      It.remove ();   }

Assuming this iterator supports the remove () operation.

via:http://stackoverflow.com/questions/602636/concurrentmodificationexception-and-a-hashmap/602660#602660

Concurrentmodificationexception and a HashMap