From the J2EE Tutorial

To reduce costs and fast-track application design and development, Java 2 Platform, Enterprise Edition (J2EE) provides a component-based approach to the design, development, assembly, and deployment of enterprise applications. The J2EE platform offers a multitiered distributed application model, reusable components, a unified security model, flexible transaction control, and Web services support through integrated data interchange on eXtensible Markup Language (XML)-based open standards and protocols.

From the Tutorial