JBoss is using its own version of xerces (found in jboss/lib), but I don't know which version.
Best practice if your application wants to use another version is to deploy your application with the other xerces.jar in one ear. Configure the ear to have its own loader repository with java2parent delegation set to false. Read the jboss-app dtd (3.2) to see how this is done. Then your application is using the other xerces while JBoss uses its own version.
Thank you for your answer. But I have another problem. I could not find the jboss-app dtd. By the side, I am using JBoss 3.0.0
If you look in docs/dtd of your distribution you should find jboss-app_3_0.dtd. I was looking in my old archived 3.0.6 so hopefully your version will have a similar file.
Hope it helps.
have no file called jboss-app_3_0.dtd