Author: Don Vines (IBM)
It has been a common practice for many IT organizations to develop applications on lightweight containers (Tomcat or WAS Liberty Profile) and to deploy them on Full Platform Java EE containers (like the WebSphere ND). There are few porting issues with this use case as you are moving a Java EE application that was developed using a subset of the Java EE APIs into a container that supports a superset of those APIs. Many articles have been written on this use case.
More recently, there has been a trend in the IT industry to replace existing Full Platform Java EE servers with lightweight containers. To do this, applications that were developed using the Full Platform Java EE APIs must be moved to lightweight containers that support a subset of those APIs. Depending on the APIs used, moving them could be quite easy or very complex.
This article series addresses the more recent trend where IT organizations are moving their existing Java EE applications from Full Platform Java EE servers, such as WebLogic Server, Oracle Application Server, and JBoss Application Server to more lightweight containers, such as the IBM WebSphere Application Server Liberty profile. In this three-part series:
- Part 1 shows you how to quickly identify those applications that can be easily migrated to the Liberty lightweight container, and those applications that will need some level of modernization to be migrated. Using the tools described in Part 1 you can determine migration suitability up front instead of part way through the migration.
- Part 2 shows you how to quickly migrate an existing Full Platform Java EE server (e.g. JBoss EAP configuration and WebLogic Server domain) and move it to the Liberty profile. Using the tools described in Part 2 allows you to quickly set up the Liberty development, test, and even production environments for this application.
- Part 3 provides you with step-by-step instructions to take an application that was coded to the J2EE 1.4 specification running on the JBoss Full Java EE Platform server, and move it to the modern IBM Liberty lightweight container. Part 3 shows you how to migrate older applications; with that you can then easily migrate more modern applications.
This article series enables you to very quickly evaluate your entire application portfolio to determine their migration suitability to Liberty. It also shows you how to migrate not only the application code, but also the server configuration required for running that application. It also enables you to take on a few of the challenging issues that you could face with older applications, such as migrating custom JAAS login modules or EJB2 beans and clients. In most cases, EJB2 can migrate fairly straightforward to EJB3, with the exception of CMP beans. In addition, links to other resources were provided that might help you with migrations to EJB3, migrations from JAX-RPC to JAX-WS, and migrations of Spring and Hibernate applications.
Following the guidelines in this article series can help you modernize your applications by moving them from old heavyweight containers like JBoss to the modern Liberty lightweight container.