Question

I have migration project which i have to start to migrate EJB2.1 enterprise web application from version 4 to version 7.1Beta(Tesla) that supports EJB2.1, I am new to migration stuffs and have looked up online but not successful in finding information regarding migration from jboss v4 to v7 migration.

Would appreciate any useful pointers.

Answer 1

I would suggest by starting out migrating to EJB 3. It is a tedious process, but pays off in a code base that is much easier to manage.

jBoss 7x is a completely different beast than the 4.x version. The biggest change is in how class loading is handled (see https://docs.jboss.org/author/display/AS7/Developer+Guide#DeveloperGuide-HowdoImigratemyapplicationfromJBossAS5orAS6toJBossAS7%3F) and how the application needs to be packaged (all in one EAR as opposed to multiple jars/wars).

Here is an example of how an ear file should be structured:

myApp.ear
     + ---- lib
     |       |------- third_party_libraries_such_as_commons-lang-2.4.jar
     |       |------- Any_Entity_Beans.jar
     |       + ------ Other_Library_files.jar
     |
    +----- META-INF
    |       +-- persistence.xml (.. possibly other config files)
    |       
    |
    | ---- application_1.jar
    | ---- application_2.jar
    + ---- webapp_1.war