public void shutdownDefaultForkJoinPool(boolean force){
    if (forkJoinPoolShutdown(defaultForkJoinPool, force)) {
      defaultForkJoinPool = null;
    }
  }
Determines the need of waiting for all tasks to be processed:
true - next task would be processed
false - next task would be cancelled
@param <T>
ambari-server/src/main/java/org/apache/ambari/server/utils/ThreadPools.java