code: public T get() {
      Barrier2 bar = _barrier;
      if( bar != null )           // Barrier may be null if task already completed
        bar.join(); // Block on the *barrier* task, which blocks until the fjtask on*Completion code runs completely
      assert isStopped();
      if (_ex!=null)
        throw new RuntimeException((Throwable)AutoBuffer.javaSerializeReadPojo(_ex));
      // Maybe null return, if the started fjtask does not actually produce a result at this Key
      return _result==null ? null : _result.get(); 
    }
docs: Blocks until the Job completes