Recently I got involved in a J2EE project which need a flexible scheduler to run on server side to perform some tasks. At a first glance, we planned to handle it by our own code, however, after given a thorough consideration, we found that there're lots of issues we need to consider: load balance, clustering, failover, synchronization etc. Finally, we noticed there's an excellent open source project can do this job very good. I'd highly recommend this open source job scheduling system: Quartz.

What is Quartz?

Quartz is an open source job scheduling system that can be integrated with, or used along side virtually any J2EE or J2SE application. Quartz can be used to create simple or complex schedules for executing tens, hundreds, or even tens-of-thousands of jobs; jobs whose tasks are defined as standard Java components or EJBs.

What can Quartz do for you?

If your application has tasks that need to occur at given moments in time, or if your system has recurring maintenance jobs then Quartz may be your ideal solution.

Sample uses of job scheduling with Quartz:

• Driving Workflow: As a new order is initially placed, schedule a Job to fire in exactly 2 hours, that will check the status of that order, and trigger a warning notification if an order confirmation message has not yet been received for the order, as well as changing the order's status to 'awaiting intervention'.
• System Maintenance: Schedule a job to dump the contents of a database into an XML file every business day (all weekdays except holidays) at 11:30 PM.

Free as in Beer?

The goal of the Quartz project is to create and maintain a fully featured, free-for-commercial-use, enterprise-class job scheduler.

The licensing of Quartz is similar to both the BSD and ASF (Apache) public licenses, which means it's free for use, even within commercial products.

Although Quartz is free, your donations are gladly accepted - they go directly to enabling the development and support of future versions of Quartz. Donations are accepted via the donation system on SourceForge.

Who is using Quartz?

Quartz is in use by thousands of people, many of whom have directly embedded Quartz in their own applications, and others who are using products that already have Quartz embedded within them.

• Vodafone Ireland - uses Quartz for scheduling tests to be carried out on systems in order to generate quality of service information.
• Covalent Technologies, Inc. - uses Quartz within their CAM product to handle anything scheduling related in the system, such as: scheduling server actions (start, restart, etc.), metric calculations, data cleanup daemons, etc.
• PartNET Inc. - uses Quartz for scheduling application events and driving workflows within many of its products.
• U.S. Department of Defence - uses Quartz at various points within an electronic commerce application, noteably order fulfillment.
• Level3 Communications - uses Quartz to drive software builds and deployments.
• Atlassian - uses Quartz within their JIRA and Confluence products.
• Cisco - uses Quartz in various in-house systems.
• Apache Jakarta - Quartz is used within (or as plugins to) several products falling under the Jakarta umbrella.
• OpenSymphony - Uses Quartz to drive the OS Workflow product.
• Spring - Quartz is used within the Spring Framework.
• XpoLog - uses Quartz within XpoLog Center in order to enable automatic technical support.