This is a pity, since probably there are lots of projects in which isolating the classloaders is not desirable, and seems that introducing JBC2 breaks it all. If I set up Class Isolation for every app I deploy, I have to bundle common core classes and model, which are stored in cache, and also start a cache for every application. This scenario for me can't work because of lots of factors, being one of them memory consumption and network traffic. Probably it would have been beter not to keep compatibility at all, and created new package structure, that could have enabled deploying JBC2 in a probably large JBossAS 4.x base. Now if I want to keep on with JBC, I have to stick with JBC1.4, which is not very performant for me, or wait till JBossAS 5, and migrate all my apps, which is very costy. I wish this had been taken into account when you decided to make api incompatible JBossCache releases 1 and 2. Hope you think more on this for latter updates, seeing there is a chance that JBC3 don't make it into JBossAS 5. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4171054#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...