public synchronized void addTarget(NotificationTarget target) throws IllegalArgumentException {
  if (target == null)   throw new IllegalArgumentException("Target is null");
  notificationTargets.add(target);
}

public synchronized void addTarget ( NotificationTarget target ) throws IllegalArgumentException { if ( target == null ) throw new IllegalArgumentException ( "Target is null" ) ; notificationTargets . add ( target ) ; }
add a notification target .
