Can TreeCache run as a second level cache inside Hibernate?
Yes. Since Hibernate 3.0 release, you can configure it to use JBoss Cache (namely, TreeCache) as a second level cache. For details, see Hibernate documentation, and also see http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossCacheHibernate Note that since Hibernate 3.0.2 and JBossCache 1.2.2, we have fixed a critical bug that depending on the usage pattern can cause deadlock during query caching.