The ASF is made up of nearly 150 top level projects which cover a wide range of technologies. Chances are if you are looking for a rewarding experience in Open Source, you are going to find it here.
Apache Struts is a free open-source framework for creating Java web applications.
The Apache Struts Project offers the Apache Struts 2 web framework which is a comprehensive and modular tooling stack for creating web-based Java applications. Struts 2, emerged from the WebWork 2 framework, is an excellent choice for teams who value elegant solutions to difficult problems.
Enterprise-class centralized version control for the masses
Subversion exists to be universally recognized and adopted as an open-source, centralized version control system characterized by its reliability as a safe haven for valuable data; the simplicity of its model and usage; and its ability to support the needs of a wide variety of users and projects, from individuals to large-scale enterprise operations.
Bean Validation API Implementation
The goal of the Apache BVal project is to deliver an implementation of the Java Bean Validation Specfication (JSR303) which is TCK compliant and works on Java SE 5 or later. The initial codebase for the project was donated to the ASF by a SGA from Agimatec GmbH and uses the Apache Software License v2.0.