Thursday, 23 October 2008

Migrating Weblogic to JBoss (1)

This is the first in a series of posts on the joys of migrating our JEE application from Weblogic to JBoss. Being JEE it should be trivial right? ;-)

The steps so far...

  1. Stripped out a couple of EJBs from our application to port as a POC
  2. Jboss download from jboss.org and installation was very quick and painless.
  3. Read some of the documentation which is fairly good, and fine when supplemented with Google, but not as good as Weblogic's
  4. JBoss runs pretty much out of the box and is very quick. Needs Sun JRE - it didn't like JRockit (which is bundled with Weblogic)
  5. Setup Oracle datasources (non XA for now) and message queues and topics. Found the documentation clear as mud and had to get help from examples
  6. Rebuilt our JEE application against the Sun JRE and JBoss EE library and found that we were using some Weblogic classes. No more.
  7. Found a free set of XSLTs to transform our Weblogic EJB deployment descriptors to JBoss. Worked mostly but needed some manual tweaking. I'll fix the XSLTs sometime.
  8. Dropped our application EAR in to the deploy folder
  9. Started JBoss
  10. Removed the CreateException from our MDB ejbCreates. JBoss complained rightly that these violated the EJB spec and even gave the section number! How cool is that?
  11. Changed the JNDI properties in our application configuration files
  12. Application deployed pretty much first time which surprised me no end
  13. Ran a little test and got some cryptic SQL error (Invalid scale size. Cannot be less than zero) which after much hunting turned out to be an Oracle-Sun JDBC incompatibility issue resolved by using -Doracle.jdbc.J2EE13Compliant=true on the server
  14. And that was pretty much it folks!

J(2)EE rocks and vendor extensions don't! Fortunately our app was built with portability in mind so it should have been this easy. Porting was an interesting exercise and much nicer than Powerpoint architecture for a change.

Initial JBoss impressions? Very favourable (apart from the imperfect documentation).

Now I have to get a cluster running and test messaging, but a cup of coffee beckons. first.

P.S. Happy to share some of the details with you if you email me
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