question: public void fireIndexedPropertyChange ( String propertyName , int index , boolean oldValue , boolean newValue ) { if ( oldValue != newValue ) { fireIndexedPropertyChange ( propertyName , index , Boolean . valueOf ( oldValue ) , Boolean . valueOf ( newValue ) ) ; } }
target:  Fires a property change of a boolean property with the given name. If the old value and the new value are not null and equal the event will not be fired.