The ASF @ 15 - The Apache Software Foundation Celebrates 15 Years of Open Source Innovation and Community Leadership http://s.apache.org/wZr
... and cheered at ApacheCon Europe http://s.apache.org/1o4
The ASF is made up of more than 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 Scout is an implementation of the JSR 93 (JAXR).
Apache Scout is an implementation of the JSR 93 (JAXR). It provides an implementation to access UDDI registries (particularly Apache jUDDI) in a standard way.
Pure Java application for load and functional testing
Apache JMeter may be used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). It can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types. You can use it to make a graphical analysis of performance or to test your server/script/object behavior under heavy concurrent load.
Apache Commons Math
The Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.