Depends on what you really want to Schedule. If you are looking at Scheduling a native job, Look for Cron Job. If you need to schedule a piece of java code as part of your application look at java.util.Timer and java.util.TimerTask. IF you need a JEE based scheduler look at Timer Service.
There are several java based products (both open source and commercial) that can help you with scheduling requirements. Couple of there are:
Quartz(Open Source): http://www.opensymphony.com/quartz/ Flux(commercial): http://www.fluxcorp.com/