@Override
    public void run() {
      synchronized (OneTaskOnlyExecutor.this) {
        future = null;
      }
      beforeExecute();
      try {
        runnable.run();
      } finally {
        afterExecute();
      }
    }
Removes the canceled tasks from the executor queue.
geode-core/src/main/java/org/apache/geode/internal/OneTaskOnlyExecutor.java