#fixed code
                              @SuppressWarnings("unchecked")
  @Override
  public void run() {
    try {
      // restart the clock.
      synchronized (callLock) {
        super.run();
        // pre-fetch one more result, for performance reasons.
        adapter.request(1);
        if (rowObserver instanceof ClientResponseObserver) {
          ((ClientResponseObserver<ReadRowsRequest, FlatRow>) rowObserver).beforeStart(adapter);
        }
        lastResponseMs = clock.currentTimeMillis();
      }
    } catch (Exception e) {
      setException(e);
    }
  }
#vulnerable code 
                              @SuppressWarnings("unchecked")
  @Override
  public void run() {
    try {
      // restart the clock.
      this.rowMerger = new RowMerger(rowObserver);
      adapter = new CallToStreamObserverAdapter();
      synchronized (callLock) {
        super.run();
        // pre-fetch one more result, for performance reasons.
        adapter.request(1);
        if (rowObserver instanceof ClientResponseObserver) {
          ((ClientResponseObserver<ReadRowsRequest, FlatRow>) rowObserver).beforeStart(adapter);
        }
        lastResponseMs = clock.currentTimeMillis();
      }
    } catch (Exception e) {
      setException(e);
    }
  } 
                            #location 7 
                            #vulnerability type THREAD_SAFETY_VIOLATION