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No-Interface View of EJB

The EJB 3.0 local client view is based on a plain old Java interface (POJI) called a local business interface. A local interface defines the business methods that are exposed to the client and that are implemented on the bean class. This separation of interface and implementation is sometimes unnecessarily cumbersome and adds little value — this is especially true for fine-grained components that are accessed locally from clients within the same module.

Local business interfaces are optional in EJB 3.1. Now you can get the same enterprise bean functionality without having to write a separate business interface. EJB 3.1 simplifies this approach by making local business interfaces optional. A bean that does not have a local business interface exposes a no-interface view. Now you can get the same enterprise bean functionality without having to write a separate business interface.

The no-interface view has the same behavior as the EJB 3.0 local view, for example, it supports features such as pass-by-reference calling semantics and transaction and security propagation. However, a no-interface view does not require a separate interface, that is, all public methods of the bean class are automatically exposed to the caller. By default, any session bean that has an empty implements clause and does not define any other local or remote client views, exposes a no-interface client view.

As is the case for a local view, the client of a no-interface view always acquires an EJB reference -- either through injection or JNDI lookup. The only difference is that the Java type of the reference is the bean class type rather than the type of a local interface.

Note that even though there is no interface, the client cannot use the new() operator to explicitly instantiate the bean class. That's because all bean invocations are made through a special EJB reference, or proxy, provided by the container. This allows the container to provide all the additional bean services such as pooling, container-managed transactions, and concurrency management.


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