junixsocket is a Java/JNI library that allows the use of Unix Domain Sockets (AF_UNIX sockets) from Java. In contrast to other implementations, junixsocket extends the Java Sockets API (java.net.Socket, java.net.SocketAddress, etc.) and even supports RMI over AF_UNIX. It is also possible to use it in conjunction with Connector/J to connect to a local MySQL server via Unix domain sockets.
eXtcos is an extensible JVM component scanner, similar to the component scanning feature of Spring. It is a small library solely focused on the task of class path scanning. It provides an easy-to-use query language for requesting the classes. This is a refreshing change to the boiler plate code you need to use the Spring classes for your own needs. You can get several different kinds of classes with just one query. You can use eXtcos for finding plug-ins for your application, classes meant to be run inside your container or framework, and the like. eXtcos is basically a base library on which other applications, containers, and frameworks can depend on.