Jakarta Messaging™ is a Java Message Oriented Middleware API for sending messages between two or more clients. It is a programming model to handle the producer-consumer messaging problem.
Jakarta WebSocket™ specifies the API that Java developers can use when they want to integrate WebSockets into their applications - both on the server side as well as on the Java client side.
Jakarta RESTful Web Services™ provides a specification document, TCK and foundational API to develop web services following the Representational State Transfer (REST) architectural
Eclipse Equinox™ is an implementation of the OSGi core framework specification, a set of bundles that implement various optional OSGi services and other infrastructure for running OSGi-based systems.