Finding duplicate classes in your WAR files with Tattletale

Have you ever found all sorts of weird errors when running your webapp because several jar files included have the same classes in different versions and the wrong one is being picked up by the application server?

Using JBoss Tattletale tool and its Tattletale Maven plugin you can easily find out if you have duplicated classes in your WAR WEB-INF/lib folder and most importantly fail the build automatically if that’s the case before it’s too late and you get bitten in production.

Just add the following plugin configuration to your WAR pom build/plugins section. It can also be used for EAR, assemblies and other types of projects.

      <phase>verify</phase> <!-- needs to run after WAR package has been built -->
    <!-- excluding some jars, if jar name contains any of these strings it won't be analyzed -->

You will need to add the JBoss Maven repository to your POM repositories section, or to your repository manager. Make sure you use the repository that only contains JBoss artifacts or you may experience conflicts between artifacts in that repo and the Maven Central repo.

Adding extra repositories is a common source of problems and makes builds longer (all repos are queried for artifacts). What I do is add an Apache Archiva proxy connector with a whitelist entry for org/jboss/** so the repo is only queried for org.jboss.* groupIds.


Eclipse IAM WTP support, now EARs too

I recently had some time to spend in Eclipse IAM, working on improving the WTP support.

Version 0.11.0 already had good support for WAR projects, including war overlays (which was a bit tricky to implement in Eclipse). Now the last builds of the coming 0.12.0 version have EAR support.

You can import your Maven EAR projects and Eclipse will recognize the Maven-generated application.xml and configure automatically the dependencies to the other WAR projects opened in the workspace, with no extra configuration from you. And from the usual WTP "Run in Server" wizard you can run the EAR project and all associated WAR files in your favorite application server.

You can install the development builds of 0.12 from until it’s released, and check the installation instructions for requirements or if you have issues. For help and feedback, we have a newsgroup at Eclipse.