17.6.2.5 Mandatory
The Container must invoke an enterprise Bean method whose transaction attribute is set to Mandatory in a client's transaction context. The client is required to call with a transaction context.
* If the client calls with a transaction context, the container invokes the enterprise Bean's method in the client's transaction context.
* If the client calls without a transaction context, the Container throws the javax.transaction.TransactionRequiredException exception if the client is a remote client, or the javax.ejb.TransactionRequiredLocalException if the client is a local client.