On p. 56 of Frits' notes,
The BM session bean starts a transaction 1. by invoking the method UserTransaction.begin(). The transaction T1 is started and will be the client's transaction context. The BM session bean invokes a method . on a CM session bean. According to the table the Container Managed session bean will now run under the transaction context (T1) of the client (ie. Bean Managed session bean). Finally the BM session bean commits the transaction by invoking UserTransaction.commit().
I think if the CM session bean's transaction attribute is REQUIRE_NEW, T1 of the BM bean will be suspended.
And if the CM session bean's transaction attribute is REQUIRE, SUPPORTS or Mandatory, T1 of the BM bean is used by this CM.
Any comments ?