joeq is a Java 2 (JDK 1.3 and 1.4) compatible virtual machine. It is unique in that it is entirely implemented in Java, leading to greater reliability, portability, maintainability, and efficiency. It is also language-independent, so code from any supported language can be seamlessly compiled, linked, and executed dynamically.
jresolver is a lightweight domain name resolver library written in pure Java. It is what RFC1034 describes as a stub resolver, i.e. it uses a single nameserver to do the hard work of resolving its queries. It operates using UDP as a transport, and has support for multithreaded querying and a robust resend and timeout mechanism.
jurlmap is a Java library for enabling your Web apps to have clean, REST-like URLs. Some of its features are a simple pattern language for brevity and convenience, direct binding of parameters to bean properties or method parameters, and configuration in plain Java and annotations.
jv4linfo is a Java API that allows to query and control video4linux (or video4linux2) devices through the JNI. The data is organized in Java objects while trying to use the same structure as the v4l/v4l2 API. It does not currently support capturing video, but it can be used to create a so-called "panel" application, an application that controls a video device, such as selecting the frequency of its tuner.