Sun Microsystems Inc.

12.4.2 java.rmi.RemoteException

The client receives the java.rmi.RemoteException as an indication of a failure to invoke an enterprise bean method or to properly complete its invocation. The exception can be thrown by the Container or by the communication subsystem between the client and the Container.

If the client receives the java.rmi.RemoteException exception from a method invocation, the client, in general, does not know if the enterprise Bean’s method has been completed or not.

If the client executes in the context of a transaction, the client’s transaction may, or may not, have been marked for rollback by the communication subsystem or target bean’s Container.

For example, the transaction would be marked for rollback if the underlying transaction service or the target Bean’s Container doubted the integrity of the data because the business method may have been partially completed. Partial completion could happen, for example, when the target bean’s method returned with a RuntimeException exception, or if the remote server crashed in the middle of executing the business method.

The transaction may not necessarily be marked for rollback. This might occur, for example, when the communication subsystem on the client-side has not been able to send the request to the server.

When a client executing in a transaction context receives a RemoteException from an enterprise bean invocation, the client may use either of the following strategies to deal with the exception:

•Discontinue the transaction. If the client is the transaction originator, it may simply rollback its transaction. If the client is not the transaction originator, it can mark the transaction for rollback or perform an action that will cause a rollback. For example, if the client is an enterprise bean, the enterprise bean may throw a RuntimeException which will cause the Container to rollback the transaction.

•Continue the transaction. The client may perform additional operations on the same or other enterprise beans, and eventually attempt to commit the transaction. If the transaction was marked for rollback at the time the RemoteException was thrown to the client, the commit will fail.

If the client chooses to continue the transaction, the client can first inquire about the transaction status to avoid fruitless computation on a transaction that has been marked for rollback. A client that is an enterprise bean with container-managed transaction demarcation can use the EJBContext.getRollbackOnly() method to test if the transaction has been marked for rollback; a client that is an enterprise bean with bean-managed transaction demarcation, and other client types, can use the UserTransaction.getStatus() method to obtain the status of the transaction.

Some implementations of EJB Servers and Containers may provide more detailed exception reporting by throwing an appropriate subclass of the java.rmi.RemoteException to the client. The following subsections describe the several subclasses of the java.rmi.RemoteException that may be thrown by the Container to give the client more information.