private void decrementWorkerCount(){
  do {
  }
 while (!compareAndDecrementWorkerCount(ctl.get()));
}

private void decrementWorkerCount ( ) { do { } while ( ! compareAndDecrementWorkerCount ( ctl . get ( ) ) ) ; }
decrements the workercount field of ctl . this is called only on abrupt termination of a thread ( see processworkerexit ) . other decrements are performed within gettask .
