public static synchronized void registerIdentityHandler(final IdentityHandler identityHandler){
  if (identityHandler == null)   throw new IllegalArgumentException("Attempt to register null IdentityHandler");
  LinkedList<IdentityHandler> newList=duplicateIdentityHandlers();
  newList.remove(identityHandler);
  newList.addFirst(identityHandler);
  identityHandlers=newList;
}

public static synchronized void registerIdentityHandler ( final IdentityHandler identityHandler ) { if ( identityHandler == null ) throw new IllegalArgumentException ( "Attempt to register null IdentityHandler" ) ; LinkedList < IdentityHandler > newList = duplicateIdentityHandlers ( ) ; newList . remove ( identityHandler ) ; newList . addFirst ( identityHandler ) ; identityHandlers = newList ; }
this method registers an identityhandler to the list of possible identityhandlers . an identityhandler will not be registered more than once .
