question: public void deregister ( Train train ) { if ( train == null ) { return ; } train . dispose ( ) ; Integer oldSize = Integer . valueOf ( _trainHashTable . size ( ) ) ; _trainHashTable . remove ( train . getId ( ) ) ; setDirtyAndFirePropertyChange ( LISTLENGTH_CHANGED_PROPERTY , oldSize , Integer . valueOf ( _trainHashTable . size ( ) ) ) ; }
target:  Forget a NamedBean Object created outside the manager.