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.
Commons Primitives is a set of collection and utility classes for primitive types. The Java language has a clear distinction between Object and primitive types. A lot of functionality is provided for Object types, including the Java Collection Framework. Relatively little functionality is provided by the JDK for primitives. This package addresses this by providing a set of utility and collection classes for primitives.
Apache Camel is a powerful open source integration framework based on known Enterprise Integration Patterns.
Apache Camel is a powerful open source integration framework based on known Enterprise Integration Patterns. Rules for Camel's routing and mediation engine can be defined in either a Java based DSL, XML or using DSLs for dynamic languages such as Groovy or Scala.
Commons Compress: working with zip, ar, jar, bz2, cpio, tar, gz, dump, pack200, lzma, 7z, arj and xz files.