EJB Enterprise Java Bean is used to develop scalable, robust and secured enterprise applications in java. Unlike RMI, middleware services such as security, transaction management etc. How to create robust and asynchronous message for distributed applications. What are messaging domains? What is JMS Queue? It is used for peer to peer messaging where a single message is delivered to only one receiver.
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EJB 3. Take a look at org. Note that the class is annotated with RemoteHome and the ejbCreate method is annotated with Init. The former annotation indicates that the bean provides a EJB 2. The latter annotation indicates that when the create method is invoked from the home interface, the bean is initialized via the ejbCreate method.
The initialization method annotated with Init name is not restricted to be ejbCreate. You can specify any other name for that method. Session2Bean illustrates the use of a local home interface. There's a very important difference between the remote and a business-remote interface. The EJB2. In this tutorial, you will notice that we are using remote and local interfaces and not business-remote and business-local interfaces.
Since we are not using any business-remote or business-local interfaces, in this tutorial, unlike the "jndibinding" tutorial, we cannot use the RemoteBinding or LocalBinding annotations to bind the EJBs. Similarly, org. DeploymentDescriptorSession1Bean and org. DeploymentDescriptorSession2Bean mimic the behavior of the first two beans, but use deployment descriptors to indicate the home interface s and initialization method s. Note the home and local-home tags that indicate the respective home interfaces.
Also, note the init-method tag that indicates the initialization method s executed when beans are created via the home interface s. To build and run the example, make sure you have installed JBoss 5. Introduction to using EJB2. Note The initialization method annotated with Init name is not restricted to be ejbCreate. Note There's a very important difference between the remote and a business-remote interface.
Note Since we are not using any business-remote or business-local interfaces, in this tutorial, unlike the "jndibinding" tutorial, we cannot use the RemoteBinding or LocalBinding annotations to bind the EJBs.
This tutorial demonstrates mechanisms for such references. Stateless3Bean , the EJB2. Stateless2Bean and the deployment descriptors for the EJB2. The ejb-ref element references the 3.
Read all about EJB 2.0
Enterprise JavaBeans 2. At just over pages, the EJB 2. The most important changes in the specification are those made to container-managed persistence CMP and the introduction of a completely new bean type, the MessageDrivenBean. The bulk of the changes in EJB 2. It's radically different from the old CMP model because it introduces an entirely new participant, the persistence manager , and a completely new way of defining container-managed fields, as well as relationships with other beans and dependent objects. The introduction of the MessageDrivenBean the message bean is also significant.