J2EE.4.1 Overview

A J2EE product provider must support a transactional application that is comprised of a combination of servlet or JSP page accessing multiple enterprise beans within a single transaction. Each component may acquire one or more connections to access one or more shared resource managers.

For example, in Figure J2EE.4-1, the call tree starts from a servlet or JSP page accessing multiple enterprise beans, which in turn may access other enterprise beans. The components access resource managers via connections.

Figure J2EE.4-1. Servlets/JSP Pages Accessing Enterprise Beans

The application component provider specifies, using a combination of programmatic and declarative transaction demarcation APIs, how the platform must manage transactions on behalf of the application.

For example, the application may require that all the components in Figure J2EE.4-1 access resources as part of a single transaction. The platform provider must provide the transaction capabilities to support such a scenario.

This specification does not define how the components and the resources are partitioned or distributed within a single J2EE product. In order to achieve the transactional semantics required by the application, the J2EE product provider is free to execute the application components sharing a transaction in the same Java virtual machine, or distribute them across multiple virtual machines.

The rest of this chapter describes the transactional requirements for a J2EE product in more detail.