The tour walks you through the process that BigTel follows to develop its customer service applications using WebLogic. During the tour, you can try out the application being described, and at the end, you are directed to additional sample applications and a simple web application that allows you to connect to and execute SQL statements on your own Oracle, Sybase, SQLServer or Informix database server. WebLogic's support of the Java Enterprise APIs is top-notch. WebLogic also supports both session and entity beans. Entity beans, on the other hand, are persistent.
Entity beans are transactional and recoverable after a system crash.
In Release 1.0 of the EJB specification, entity beans do not need to be supported by EJB products, so WebLogic is technically ahead of the game by supporting them. Servlets are Java classes that run on the server and respond to HTTP requests. Servlets operate as a part of the Java server, and are, therefore, protected by its security and are able to take advantage of the Servlet support services offered by WebLogic. These methods of developing web applications have become popular because they allow you to combine application logic and HTML presentation code into one file that is interpreted or compiled by the application server before returning HTML to the requesting client. I'm not saying this is the correct way to write an application, I'm just explaining why it's popular.