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.
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.
Java-based template engine
Velocity is a Java-based template engine. It permits anyone to use a simple yet powerful template language to reference objects defined in Java code. When Velocity is used for web development, Web designers can work in parallel with Java programmers to develop web sites according to the Model-View-Controller (MVC) model, meaning that web page designers can focus solely on creating a site that looks good, and programmers can focus solely on writing top-notch code. Velocity separates Java code from the web pages, making the web site more maintainable over its lifespan and providing a viable alternative to Java Server Pages...