Java EE Tutorial

Java EE Tutorial

1. Entity Bean
There are two kinds of enterprise beans: session beans and message-driven beans. A session bean represents a transient conversation with a client. When the client finishes executing, the session bean and its data are gone. A message-driven beancombines features of a session bean and a message listener, allowing a business component to receive messages asynchronously. Commonly, these are Java Message Service (JMS) messages.
In Java EE 5, entity beans have been replaced by Java persistence API entities. An entity represents persistent data stored in one row of a database table. If the client terminates, or if the server shuts down, the persistence manager ensures that the entity data is saved.
2. JavaServer Pages Standard Tag Library
The JavaServer Pages Standard Tag Library (JSTL) encapsulates core functionality common to many JSP applications. Instead of mixing tags from numerous vendors in your JSP applications, you employ a single, standard set of tags. This standardization allows you to deploy your applications on any JSP container that supports JSTL and makes it more likely that the implementation of the tags is optimized.
JSTL has iterator and conditional tags for handling flow control, tags for manipulating XML documents, internationalization tags, tags for accessing databases using SQL, and commonly used functions