The Netty project is an effort to provide an asynchronous, event-driven network application framework and tools for rapid development of maintainable, high-performance, high-scalability protocol servers and clients. In other words, Netty is a NIO client server framework that enables quick and easy development of network applications such as protocol servers and clients. It simplifies and streamlines network programming such as TCP and UDP socket servers.
GreenMail is a suite of email servers for testing purposes and sandbox development. It supports SMTP, POP3, and IMAP (including SSL) and can be embedded into any Java application or unit test. The GreenMail Service (SAR) extension runs as a JBoss embedded developer mail server sandbox, manageable via JMX.
WSO2 WSF/Spring provides an amazingly simple "Code First" approach to create Web services for the Spring user. This framework integrates the Apache Axis2 Web services engine into Spring. Thus, it provides all the power and versatility of the Axis2 engine to the Spring user. With just a few entries in the application context, this lets Spring users enjoy the benefits of Service Oriented Architecture using Web services in their applications.