Difference in these APIs is that Thread.speep(long millis) causes to sleep the current
thread for given period of time.
It does not release the monitor which it has been aquired.. While Thread.wait(long millis) causes to wait for given period of time or will also exit from wait condn if any other thread calls Thread.notify() or Thread.notifyAll() on the same object on which this thread is synchronized.
Also it releases the monitor that it has aquired. Now in your case as you just want to pause the current thread for particular period of time should use Thread.speep(1000).