Enterprise JavaBeans (EJBs) are Java server-side components.Ý They are generally used as middleware components in large distributed applications, connecting the data at the back end to the users at the front end. AppComposer can work with any EJB 1.1 or higher compliant bean. EJBs that are compliant with the 1.0 specification can be used in AppComposer if an XML deployment descriptor is included in the Java archive (jar) file with the beans.
Despite their similar names, Enterprise JavaBeans and JavaBeans are very distinct and different.Ý Both JavaBeans and Enterprise JavaBeans are types of component models, but do not share a programming or usage model.Ý JavaBeans are not Enterprise JavaBeans, and Enterprise JavaBeans are not JavaBeans.Ý JavaBeans tend to be visual, client-side components, though they can be non-visual.Ý Enterprise JavaBeans are server-side, remote, non-visual components.Ý See Sun Microsystems' web site for a more detailed discussion of EJBs.Ý
This example uses a preconstructed entity bean, SimpleBank, which talks to an HSQL database to get information about bank accounts.Ý To provide access to this information through a browser, you will build a servlet that calls the EJB and formats the results for display in a web page.
Note: You cannot run EJBs in a regular Java VM.Ý You must run them within an EJB Application Server.
In this tutorial, you will learn how to: