I think A is right. When the method Bob is being called, it creates new transaction for it and method Aby gets suspended until the Bob transaction is committed. Also note that it has to be method from some other bean to make it transactional, methods called from the same bean do not act as … Read more
Java bean is just a set of conventions. EJB is a standard for J2EE business components. Specifically a Java bean: has a public default constructor; readable property methods precedes with “get”; writable property methods precedes with “set”; and is Serializable. For example, a Java bean with a property of “margin” would minimally look like this: … Read more
Is this the correct way of doing things? Apart from performing business logic the inefficient way in a managed bean getter method, and using a too broad managed bean scope, it looks okay. If you move the service call from the getter method to a @PostConstruct method and use either @RequestScoped or @ViewScoped instead of … Read more
The @EJB annotation (and @Resource, @WebServiceRef, etc.) serves two purposes: It declares a reference in the component namespace. For example, @EJB(name=”myEJB”) creates a reference java:comp/env/myEJB. If you annotate a field and do not specify a name, then it creates a reference java:comp/env/com.example.MyClass/myField. If the annotation is declared on a field or setter method, then the … Read more
You’re seeing the same output because there is only one client accessing the EJB at a time. The application server is able to recycle the same stateless EJB object for each call. If you try a concurrent access – multiple clients at the same time – you’ll see new stateless instances appearing. Note that, depending … Read more
These are frameworks for different layers. JSF is for the view (web) layer, it’s a component oriented framework (every part of a page is a component, it has state) like Wicket or Tapestry, and unlike Action frameworks like Spring MVC, Struts or Stripes Books: Core JavaServer Faces (3rd Edition) Tutorials: CoreServlets.com EJB 3.x is a … Read more
A JavaBean is just a plain old Java object that conforms to certain conventions including the use of accessor functions (getFoo/setFoo) for member access, provision of a default constructor and a few other things like that. An Enterprise JavaBean is a component in a Java EE application server which comes in several flavours, the details … Read more
First of all, Spring and EJB(+JTA) are competing technologies and usually not to be used together in the same application. Choose the one or the other. Spring or EJB(+JTA). I won’t tell you which to choose, I will only tell you a bit of history and the facts so that you can easier make the … Read more
Check out EJB 3.1 @Asynchronous methods. This is exactly what they are for. Small example that uses OpenEJB 4.0.0-SNAPSHOTs. Here we have a @Singleton bean with one method marked @Asynchronous. Every time that method is invoked by anyone, in this case your JSF managed bean, it will immediately return regardless of how long the method … Read more
They were most likely looking for examples of web frameworks – for example, JSF is a component-based framework, and Struts is a request-based framework. Request-based frameworks generally make it clear through their APIs that they’re working with parsing an HTML request / generating an HTML response, while Component-based frameworks attempt to abstract this away and … Read more