MDB is Message driven bean. It is a event driven bean which is called when a messaeg is received in a queue or a topic space hence it act a listener to Queue and Topic.

I am not getting that how you want to connect it to frontend.

Kindly elaborate your issue so that we can do something for it.

An entity bean represents persistent global data from the database; a session bean represents transient user-specific data that will die when the user disconnects (ends his session). Generally, the session beans implement business methods (e.g. Bank.transferFunds) that call entity beans (e.g. Account.deposit, Account.withdraw). A message-driven bean is an enterprise bean that allows J2EE applications to process messages asynchronously. It acts as a JMS message listener, which is similar to an event listener except that it receives messages instead of events. The messages may be sent by any J2EE component--an application client, another enterprise bean, or a Web component--or by a JMS application or system that does not use J2EE technology.

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A stateless session bean is a type of enterprise bean in Java EE that doesn't maintain any conversational state with clients. Each client request is treated independently, and the server can choose any available instance of the stateless session bean to handle the request. Statelessness allows for efficient use of resources and parallel processing since the server doesn't have to keep track of the state of each client.

MDSE is the abbreviation for merchandise. It can also stand for Model-Driven Software Engineering, Message Delivery Service Element, and Model Driven Software Evolution.