I should have explained my question in more detail. The Javadoc of the ItemManager states that there's one ItemManager per Session: it is created in the constructor of SessionImpl. Sessions are not thread-safe by specification. Because some methods in the ItemManager are synchronized, an ItemManager instance of a Sesssion can also be accessed by other threads than the one that is using the Session that created that ItemManager. I am just wondering when that could happen.
our official statement still is you may use multiple threads on a session that just read but a single thread on a session that writes. in addition there's also the scenario where one thread saves changes on session and those changes get propagated to other sessions that are accessed by other threads.
as for multiple threads on a single session instance I personally prefer a more coarse grained synchronization to avoid monitor contention. see: JCR-890.
regards marcel
