In our previous web service example, we saw how we can expose a Plain Old Java Object (POJO) as a web service by packaging it in a web application and adding a few annotations to it. This makes it very easy to create web services deployed in a web application.

When working with an EJB module project, we can have stateless session beans exposed as web services. This way, they can be accessed by clients written in languages other than Java. Exposing stateless session beans as web services has the effect of allowing our web services to take advantage of all the features available to EJBs, such as transaction management and aspect oriented programming.

There are two ways of exposing a session bean as a web service. When creating a new web service in an EJB module project, the web service will automatically be implemented as a stateless session bean. Additionally, existing session beans in an EJB module project can be exposed as a web service.