I'm J2EE noob, am really appreciate if anybody can help me to clear my doubt.
EJB has 3 types:
a) Session Bean
- Stateless (use in normal login mechanism)
- Stateful (use in shopping cart)
b) Entity Bean - i don't know where and when is it suit to use
- BMP (conn to db using DAO)
- CMP (conn to db directly)
c) Message Driven Bean - i am not sure of this usage too
However, is MDB = MBean ? can anybody tell when is it suitable to use, and the purpose?
Also, i am confuse with JMS & JMX too.
MDB != MBean
A message driven bean can be used to implement asynchronous communication between more applications. JMS offers two mechanisms : a topic and a queue
- topic : The sender sends a message to the topic and this message is automaticaly forwarded to the members registed to the topic. When a client wants to get the messages he must register to the topic.
- queue : This is similar to a mail box. A client has a mail box and the sender directly address the message to a mail box. The message is stored in the mail box and the client (receiver) must look in his mail box and retrieve the messages
MBean -> Management Bean
These beans are used to manage an application. For more information (mlet, notification, relation, ...) consult the specification of JMX.