Ver.2.1 OS: Windows NT,2000       TOUR     EJAS - The Enterprise Java Application Server is a framework for developing and executing Distributed Applications. These Applications provide system-level services such as Transaction Management, Security, Client Connectivity and Database Access.     EJAS - The Enterprise Java Application Server Architecture To create a Distributed Application with the EJAS - Enterprise Java Application Server, you need to code the business logic in reusable components called Enterprise Java Beans. These beans contain business methods that are invoked by the Clients.	VIEW FEATURES       BUY
	EJB Container Enterprise Beans reside in an Enterprise Java Beans Container, which runs on the EJAS. Its primary role is to serve as a buffer between an EJB and the outside world. The Container controls the Enterprise Beans and provides them with important system-level Services. The Container provides the following services to the Enterprise Bean:      þ Transaction Management      þ Security      þ Remote Client Connectivity      þ Life Cycle Management      þ Database Connection Pooling     Configuring EJAS Parameters: To configure the EJAS parameters, like Listener Port of EJAS Server, Session Timeout of Client, Transaction Timeout, Passivate Directory, EJB Directory (Where the EJB Beans Archive exists).
	Transaction Management: EJAS - Enterprise Java Application Server provides Automatic Database Access for Bean Developers. Using EJB "Container-Managed" persistence, the EJAS Container provides the mapping from the user-developed bean to the underlying database. You do not have to code transaction boundaries in the Enterprise Bean. The code required to control distributed transactions can be quite complex. Instead of writing and debugging complex code, you can simply declare the Enterprise Bean's transactional properties in the deployment descriptor file. The container reads the file and handles the Enterprise Bean's transactions for you.
	Security: The Container permits only authorized Clients to invoke an Enterprise Bean's Methods. Each Client belongs to particular role, and each role is permitted to invoke certain methods .You declare the roles and the methods they may invoke in the Enterprise Bean's Deployment Descriptor. Because of this declarative approach, you don't need to code routines that enforce security.     Remote Client Connectivity: The Container manages low-level communications between Clients and Enterprise Beans. After an Enterprise Bean has been created, a client invokes methods on it, as if it were in the same virtual Machine.
	Life Cycle Management: An Enterprise Bean passes through several states during its lifetime. The Container creates the Enterprise Bean, moves it between a pool of available instances and the active state, and finally, removes it. Although the Client calls methods to create and remove an Enterprise bean, the container performs these tasks behind the scenes.     Database Connection Pooling: A Database Connection is a costly resource. Obtaining a Database Connection is time-consuming and the number of connections may be limited. To alleviate these problems, the container manages a pool of Database Connections. An Enterprise Bean can quickly obtain a connection from the pool. After the Bean releases the connection, it may be re-used by another Bean.
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