This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
PlaceBidBean has two PostConstruct callbacks initBean() and initializeBean(). Exception: 17:37:54,031 WARN [ServiceController] Problem starting service jboss.j2ee:service=EJB3,module=myEJB-ejb.jar java.lang.RuntimeException: An exception occurred initialising interceptors for class com.ejb3inaction.actionbazaar.buslogic.PlaceBidBean.addBid at org.jboss.ejb3.interceptor.EJB3InterceptorsFactory.createPerJoinpoint(EJB3InterceptorsFactory.java:108) at org.jboss.aop.advice.AspectFactoryDelegator.createPerJoinpoint(AspectFactoryDelegator.java:119) at org.jboss.aop.advice.ScopedInterceptorFactory.create(ScopedInterceptorFactory.java:113) at org.jboss.aop.Advisor.createInterceptorChain(Advisor.java:618) Caused by: java.lang.RuntimeException: Interceptors can only have one post-construct/@PostConstruct method - com.ejb3inaction.actionbazaar.buslogic.PlaceBidBean at org.jboss.ejb3.interceptor.InterceptorInfo.setPostConstruct(InterceptorInfo.java:147) at org.jboss.ejb3.interceptor.InterceptorInfoRepository$AnnotationInitialiser.getInfo(InterceptorInfoRepository.java:688) at org.jboss.ejb3.interceptor.InterceptorInfoRepository.initialiseFromAnnotations(InterceptorInfoRepository.java:481) at org.jboss.ejb3.interceptor.InterceptorInfoRepository.getOrInitialiseFromAnnotations(InterceptorInfoRepository.java:466)
1) Why multiple callbacks are not allowed for stateless session bean? 2) I dont understand why the exception has "Interceptors" words. I have just used a plain stateless session bean as shown in the code. Please clarify. What about PreDestroy, PrePassivate and PostActivate callbacks? 3) Is the book incorrect?
You can have mutiple callbacks for a given bean.It is correct.
But the condition is you cannot define mutiple callback methods for a single lifecycle event in a Single bean class
Ex. In the above example, you mentioned 2 callback methods initBean() and initializeBean() for a PostConstuct event in 1 bean class PlcaeBidBean. This is wrong
However you can remove the one of the postConstruct methods and can put it in bean superclass or also in Bean Interceptor classes so that both methods will be called.
Simply to say, atmost 1 lifecycle callback method should be declared for each lifecycle event in each class ( it can be bean class or its super class or its interceptor class)
2. Lifecycle callback methods are also called as lifecycle callback interceptor methods. I think because of that the exception has "Interceptors" words. Not sure
3. EJB3 in Action is really good book for EJB3 beginners. The authors did an excellent work. The points mentioned by the authors are from the Specs only. But there are few concepts which they need to explain clearly.
I looked at the questions raised by you. Really good. I'm also looking for answers for some questions. Let's see
------------------------------------- LakshmiNarayana Kodali SCJP 5(98%), SCWCD(100%), SCBCD in progress
Joined: Aug 05, 2006
EJB3 in Action is really good book for EJB3 beginners. The authors did an excellent work. The points mentioned by the authors are from the Specs only. But there are few concepts which they need to explain clearly.
Please don't get me wrong. I highly appreciate their work. Infact am reading EJB in Action to understand about EJB. Before reading the book i had 0 knowledge on EJB.
Yes in "EJB in Action" (2007) is written "Note that you can have multiple PostConstruct and PreDestroy callbacks for a given bean (although this is seldom used) in a class or in a separate interceptor class (discussed in chapter 5)." . Which can direct to the false assumption that in single class definition you can have more then one @PostConstruct and @PreDestroy annotated method.