One solution I use is to have a common jar that contains the common classes you want to share and add it as a java module to your application.xml.
Modules have to be an EJB, WAR or application jar. Listing any old jar as a module only works in JBoss. WLS, for exampe, won't load a plain jar file.
Historically I have used Class-Path settings but was hoping there was now a more convenient yet portable solution. I guess I will use the application.xml for now, then use Class-Path if and when we need to port this.
set your common jar un your EAR and use ClassPath in entiotybean.jar to depend on this common jar
That's usually what I've done but that adds another file (manifest) and changes the build script and then you've got to repeat that for all the jars that use common.jar. It seems like a lot of needless tinkering when it should just load jars in the base of the ear listed as "java" modules.
In fact JBoss does load "java" modules whether they contain a client application or not. Maybe it's a bug but it's VERY convenient. Only thing is the load order isn't specified, but it seems to work.