question: @ Override public void stop ( ) { CountDownLatch latch = stopped ; Thread oldThread = thread . getAndUpdate ( null ) ; if ( oldThread != null && latch != null ) { try { latch . await ( 10 , TimeUnit . SECONDS ) ; } catch ( InterruptedException e ) { Thread . interrupted ( ) ; } } }
target:  Stop this executor from executing, and block until the thread has completed all work (or until the timeout has occurred). <p> Calling this method when already stopped has no effect.