code: protected boolean scheduleImpl(Runnable task,
                                   ClassLoader loader,
                                   long expireTime,
                                   boolean isPriority,
                                   boolean isQueueIfFull,
                                   boolean isWakeScheduler)
    {
      Objects.requireNonNull(task);
      
      RunnableItem taskItem = new RunnableItem(task, loader);
      
      return schedule(taskItem);
    }
docs: main scheduling implementation class.