Vibur Object Pool is a general-use concurrent Java object pool which provides both validating and non-validating pool implementations. The pool is built entirely using the standard Java concurrency utilities, does not use any synchronized blocks/methods, and does not have any external dependencies. This pool is an excellent choice for pooling/caching of expensive to create Java objects such as database connections or other socket connections to remote hosts, and similar.
JS-Collider is an event-driven Java network NIO framework. It is designed to provide maximum performance and scalability for applications having not too many connections but significant amounts of network traffic (both incoming and outgoing). Performance and scalability are achieved via lock free algorithms and atomic states usage. It supports UDP (with multicast) as well. One of the implementation points is to avoid unsafe cheating; it should work the same way on all JVMs (Java 1.7). It supports shared memory IPC.