code: public static synchronized void cancel(TimerTask task) {
          if (task == null) {
              return;
          }
          task.cancel();
          usageCount.decrementAndGet();
          if (usageCount.get() == 0) {
              timer.cancel();
              timer = null;
          }
      }
docs: Remove the specified eviction task from the timer.
  
  @param task Task to be scheduled