If you're unfamiliar with Java Scheduler, Robert Heidasch's latest SAP Professional Journal article, "Create New Jobs and Schedule Existing Ones with Java Scheduler in SAP NetWeaver AS Java," is a great place to start.
Java Scheduler is similar to the ABAP Scheduler -- transactions SM36 and SM37 in SAP NetWeaver AS ABAP -- which is an ABAP-based job scheduler. You can schedule jobs based on times you want them to run, or trigger them to run after certain events. I'll let Robert take it from there:
Because SAP NetWeaver AS Java implements an object-oriented architectural approach, Java Scheduler uses the same approach in developing jobs. This means the business application provider defines one or many jobs based on Java message-driven beans (classes written in Java that allow you to encapsulate many objects into a single object) that implement the business process or logic in the background process.
Robert goes on to explain the features of Java Scheduler, as well as the configuration involved, and the code you can insert in SAP NetWeaver Developer Studio to get you going. He also issues this performance-related cautionary note:
Java Scheduler allows you to schedule an unlimited number of jobs per day, but this may have a significant impact on the performance of your system. Additionally, each job may require a different amount of system resources, so you should try to reduce the number of jobs. In case of performance problems, investigate their reasons and optimize the job configuration. Additionally, Java Scheduler persists all information about past, current, and future jobs in the database of SAP NetWeaver AS Java. This information is required for the data integrity and failover reasons, but its amount may cause system overload problems, such as if a task is executed several times a second.
To read the full article, subscribers to SAP Professional Journal can go here.