There is no shortage of well-known reasons for wanting to migrate your Java EE web application to open source Tomcat. But without development experience with both your current Java EE application server as well as with Tomcat, it isn’t clear what you must change in your Java EE application to get it to run properly on Tomcat. The benefits of being able to run it on Tomcat are significant — for example, Tomcat is free to run in production, and Tomcat is faster at tasks such as redeployment.
It’s easy to migrate your Java EE app to Tomcat as long as it’s mainly a web container app, and as long as you know what you might need to change in your app’s code to get it running on Tomcat. Even if your Java EE app uses other Java EE server components, you can still migrate it to run on Tomcat if you add the open source counterparts of those Java EE components to Tomcat — you would need to know which open source components to add, and some instructions on how to make them work with Tomcat. For example, if your app used EJB, you could add OpenEJB to Tomcat.
For the purposes of this blog, I’ll focus on migrating from Weblogic to Tomcat, and on migrating from WebSphere to Tomcat. But, it’s a similar process if you’re migrating from other app servers such as JBoss or Glassfish.