Signals that a modification has been made to a data structure at the same time some other operation is in progress and that, as a result, the correctness of the ongoing operation cannot be guaranteed. It is typically thrown by an Iterator or ListIterator object to stop an iteration if it detects that the underlying collection has been modified while the iteration is in progress.

Figure 16-11. java.util.ConcurrentModificationException

public class ConcurrentModificationException extends RuntimeException {
// Public Constructors
     public ConcurrentModificationException( );  
     public ConcurrentModificationException(String message);  
}