Java EE example project

Question

Hello!

I am currently in the process of learing about Java EE, EJB3 and . So far I am running a JBoss application server and a Oracle database. I have written a stateful session bean which retrieves data from the database through JPA entities.

My goal is to have a simple client speaking to a server by calling methods in a stateful bean. But I have too little experience to know how granular these beans should be, how the should interact with my entity beans and so on.

I am far from perfect, but books and simple tutorials don't really help anymore. I looked for open source projects that are actually using these kind of technology in order to get the idea how to design my application. A websearch did not bring up much, except a PetStore example from 2006. I would be glad if anyone could point me to some useful resource, not necessartily a real project, but maybe more advanced examples.

Answer 1

I've found "EJB 3 In Action" book as very useful to understand how to develop your beans.

Answer 2

You can find some sample apps here:

• http://www.laliluna.de/EJB-3-tutorials.html
• http://openejb.apache.org/ejb3-sample-applications.html
• http://www.packtpub.com/article/Building-JSF-EJB3-Applications

Answer 3

Sounds like you're looking to learn "what kind of logic to I code in the EJB tier" instead of "how do I code the EJB tier".

The textbook answer would be to say "most business logic should be implemented at the EJB tier".

Practically speaking, I would base my decisions on something according to this workflow:

1. Suppose my business case is to implement a Bank Account Inquiry service. So, I roughly know that an AccountInquiryService is required.
2. Typically, the main channel where this service would be invoked is from a web tier, i.e. a web application where the user can perform inquiries on his accounts.
3. However, in the interest of code reuse, I figure that there may be a use case, where I may need to code a Java desktop client that will also perform account inquiries.
4. So, I try to construct the AccountInquiryService such that the same methods are applicable from both the web and desktop client tiers. I must not need to add different methods just to be able make both channels work.

Sorry if I got the gist of your question wrong. Hope this helps.