A content repository implementation is required to provide a thread-safe implementation of all methods of javax.jcr.Repository.
A content repository implementation is not required to provide thread-safe implementations of other interfaces. As a consequence, an application which concurrently or sequentially operates against objects having affinity to a particular Session through more than one thread must provide synchronization sufficient to ensure no more than one thread concurrently operates against that Session and changes made by one thread are visible to other threads.