How to extend AbstractScheduledService.Scheduler

How to extend AbstractScheduledService.Scheduler

I am trying to extend AbstractScheduledService.Scheduler so that I can use
a schedule that stores initial delay and period in instance variable.
I am trying with the following
public class ScannerScheduler extends AbstractScheduledService.Scheduler {
@Override
public final Future<?> schedule(AbstractService as,
ScheduledExecutorService ses, Runnable task) {
Executors.newSingleThreadScheduledExecutor()
.scheduleAtFixedRate(task, 0, 1, TimeUnit.DAYS);
}
}
But the compiler still complains with:
ScannerScheduler is not abstract and does not override abstract method
schedule(AbstractService,ScheduledExecutorService,Runnable) in Scheduler
What am I missing?
Thanks a lot in advance.
Stefano