I'm deploying several web applications on JBoss 3.0.7 running on Solaris.
These web applications share some EJBs which are deployed in a separate
EAR. The EJBs in the EAR share some common core classes (value objects,
PKs, exceptions) which are packaged in a "support" jar which is then
referenced in the manifest classpath of each EJB jar. The support jar
is also copied to each of the WARs' WEB-INF/lib directories so that the
web applications also have access to these common classes. Each EJB jar
also has a companion client jar containing just the remote and home
interfaces of each EJB; these are also copied to both the WAR lib directories
and the EAR directory.
This setup has worked for about a year now, and now all of a sudden we're
getting linkage errors and class cast exceptions on just one of our lab
test machines. Other machines running a very similar build are working OK.
The class that's involved in the errors appears to be one of the classes
in the common support jar.
I read the document by Scott Stark on classloading quite a while back,
and recall that linkage errors and class cast errors can be an indication
of classloading problems. But what am I doing wrong here ? I think that
the kinds of things that I'm doing, separate support jar mentioned on
manifest classpath, and separate client jars for interfaces, is pretty
common usage these days. Anyone have any problems using a similar
approach ?
EAR:
--> MyEjb1.jar
--> META-INF/MANIFEST.MF
--> Class-Path: EjbSupport.jar OtherEjbClient.jar
MyEjb1Impl.class
--> EjbSupport.jar
--> SessionLocator.class
--> CommonPK.class
--> AppSpecificException.class
--> MyEjb1Client.jar
--> MyEjb1Home.class
--> MyEjb1Remote.class
--> OtherEjbClient.jar
--> OtherEjbHome.class
--> OtherEjbRemote.class
...and so on...
WAR:
--> WEB-INF
--> lib
--> MyGuiServlets.jar
--> CompiledJSPs.jar
--> EjbSupport.jar
--> MyEjb1Client.jar
--> OtherEjbClient.jar
