question: @ Override public void doNotify ( ) throws Exception { log . info ( "Received notification that related system properties are changed" ) ; ScheduledExecutorService svc = service ; if ( svc != null ) { try { svc . schedule ( ( Callable < Object > ) this , 0L , TimeUnit . MICROSECONDS ) ; } catch ( RejectedExecutionException ex ) { if ( svc . isShutdown ( ) ) { log . info ( "Property change notification ignored because this node is no longer backup leader." ) ; } else { throw ex ; } } } else { log . info ( "Property change notification ignored because this node is no longer backup leader." ) ; } }
target:  Called when related system properties are changed, and we need to reschedule