I have had that already and it even may (and usually does) give the error at the very first run. And there never is a permGen error in the log. I am not sure but I am relating it with me moving the library jars out of the project (to have a smaller .ear file) and adding these jars to the application server's classpath. I also have not managed log4j to find log4j.properties and initialize properly and after a lot of googling I have a feeling that it may be something to do with the class loader. There I have really near-to-zero knowledge about class loaders and about how an application server employs one (or many) Anything? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4038240#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...