Why ThreadPoolTaskScheduler doesn't support scheduling for Callable

I am doing some experiments and I did know about Spring ThreadPoolTaskScheduler API

This method only has a schedule :

ScheduledFuture<?>  schedule(Runnable task, Date startTime)
ScheduledFuture<?>  schedule(Runnable task, Trigger trigger)

      

        
        
        
      

    

Why ThreadPoolTaskScheduler does not support schedule for Callable ?

If I check the JDK ScheduledThreadPoolExecutor API , I can see these methods:

ScheduledFuture<?>  schedule(Runnable command, long delay, TimeUnit unit)
<V> ScheduledFuture<V>  schedule(Callable<V> callable, long delay, TimeUnit unit)

      

        
        
        
      

    

On GitHub I see that ThreadPoolTaskScheduler createExecutor method creates ScheduledThreadPoolExecutor

I don't know why Spring did this.

Thanks in advance.