Definition of stateful bean and stateless Bean

Stateful Session Bean: each user has its own unique instance,Bean maintains user information, that is, "stateful"The bean life cycle ends once the user dies (the call ends or the instance ends.That is, each user will initially get an initial Bean.

Stateless Session Bean: Once instantiated, the bean is added to the session pool, which can be shared by all users. Even if the user has been extinct, the bean life cycle may not end, and it may still exist in the session pool for other users to call.Because there is no specific user, the status of a user cannot be maintained, so it is called stateless bean.. However, the stateless Session Bean is not stateless. If it has its own attributes (variables), these variables will be affected by all users who call it, this must be noted in practical applications.