Handling Exceptions - The Java EE 5 Tutorial (original) (raw)
2. Using the Tutorial Examples
3. Getting Started with Web Applications
5. JavaServer Pages Technology
7. JavaServer Pages Standard Tag Library
10. JavaServer Faces Technology
11. Using JavaServer Faces Technology in JSP Pages
12. Developing with JavaServer Faces Technology
13. Creating Custom UI Components
14. Configuring JavaServer Faces Applications
15. Internationalizing and Localizing Web Applications
16. Building Web Services with JAX-WS
17. Binding between XML Schema and Java Classes
19. SOAP with Attachments API for Java
21. Getting Started with Enterprise Beans
Building, Packaging, Deploying, and Running the cart Example
Building, Packaging, and Deploying the cart Example Using NetBeans IDE
Running the cart Application Client Using NetBeans IDE
Building, Packaging, and Deploying the cart Example Using Ant
Running the cart Application Client Using Ant
A Web Service Example: helloservice
The Web Service Endpoint Implementation Class
Stateless Session Bean Implementation Class
Building, Packaging, Deploying, and Testing the helloservice Example
Building, Packaging, and Deploying the helloservice Example Using NetBeans IDE
Building, Packaging, and Deploying the helloservice Example Using Ant
Testing the Service without a Client
Building, Packaging, Deploying, and Running the timersession Example
Building, Packaging, Deploying, and Running the timersession Example Using NetBeans IDE
Building, Packaging, and Deploying the timersession Example Using Ant
Running the timersession Application Client Using Ant
23. A Message-Driven Bean Example
24. Introduction to the Java Persistence API
25. Persistence in the Web Tier
26. Persistence in the EJB Tier
27. The Java Persistence Query Language
28. Introduction to Security in the Java EE Platform
29. Securing Java EE Applications
31. The Java Message Service API
32. Java EE Examples Using the JMS API
36. The Coffee Break Application
37. The Duke's Bank Application
Handling Exceptions
The exceptions thrown by enterprise beans fall into two categories: system and application.
A system exception indicates a problem with the services that support an application. Examples of these problems include the following: a connection to an external resource cannot be obtained or an injected resource cannot be found. If your enterprise bean encounters a system-level problem, it should throw a javax.ejb.EJBException. Because the EJBException is a subclass of the RuntimeException, you do not have to specify it in thethrows clause of the method declaration. If a system exception is thrown, the EJB container might destroy the bean instance. Therefore, a system exception cannot be handled by the bean’s client program; it requires intervention by a system administrator.
An application exception signals an error in the business logic of an enterprise bean. Application exceptions are typically exceptions that you’ve coded yourself, such as the BookException thrown by the business methods of the CartBean example. When an enterprise bean throws an application exception, the container does not wrap it in another exception. The client should be able to handle any application exception it receives.
If a system exception occurs within a transaction, the EJB container rolls back the transaction. However, if an application exception is thrown within a transaction, the container does not roll back the transaction.
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