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.
JTelIRC is an advanced IRC framework for Java. It is mainly intended for writing automated clients ("bots"), but may be used for normal clients as well. It provides an intuitive and well documented Java interface to IRC and makes it extremely easy to write advanced clients quickly.
RapidInformer is a notification system that empowers people to stay connected and take control of the information flow. It enables users to control all notifications they will receive from a single Web application in a consistent manner rather than dealing with different capabilities of each enterprise application, and work with enterprise systems by executing commands directly from instant messaging clients (or the Web application).