Enterprise JavaBeans 3.1, 6th Edition

Exceptions and Transactions

Exceptions have a large impact on the outcome of transactions.

Application Exceptions Versus System Exceptions

System exceptions represent unknown internal errors. The EJB container throws system exceptions when it encounters an internal application server failure. Business logic can throw system exceptions when it wants to abort the business process. Application exceptions are exceptions that are part of your business logic. They denote a strongly typed definition of a specific business problem or failure but do not necessarily abort or roll back the business process.

System exceptions

System exceptions include java.lang.RuntimeException and its subclasses. EJBException is a subclass of RuntimeException, so it is considered a system exception. System exceptions also include java.rmi.RemoteException and its subclasses. The RuntimeException and RemoteException subclasses differ in that they can be turned into application exceptions using the @javax.ejb.ApplicationException annotation. This annotation is discussed later in this chapter.

System exceptions always cause a transaction to roll back when they are thrown from an enterprise bean method. Any RuntimeException not annotated with @ApplicationException that is thrown within a business method (for instance, EJBException, NullPointerException, IndexOutOfBoundsException, and so on) is handled by the container automatically and results in a transaction rollback. In Java, RuntimeException types do not need to ...