Can you describe what you mean by 'deploy new jars to JBoss', where do you put them?
Also are any messages displayed in the console for redeployment?
If you're talking about EJB jars, or other stuff in the deploy directory, then redeploying will cause the classes to be reloaded. If you mean jars in the lib directory, then you have to reboot.
I am talking about hot deployment into the default deploy directory.
I have several JARs with classes in one JAR referring to classes in another. One I reload one of them, it seems like the links are broken between classes in the JARs that remained unchanged and the JAR that was redeployed.