WorkspaceNodes are used by the optimistic locking interceptors so changes are not made to the nodes in the cache directly, but rather to the workspace nodes stored in the transaction workspace. NodeSPI has access to locking mechanisms that don't exist in WorkspaceNodes (since each tx will have its own copy of a workspace node, there is no concurrency here) There is no "access" to an SPI interface, as such. the SPIs are passed in to CacheLoader and CacheListener interfaces. Is there anything specific PojoCache needs from the SPI interfaces? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3994652#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...