Akeni LAN Messenger
a cross-platform instant messenger client. It is a P2P program that works on your LAN without the need of an Internet connection or a dedicated server. The client has an user interface similar to AIM, ICQ, or MSN Messenger
a Java instant messaging client library. It can run as a standalone app in console mode, send and receive type 1 text messages, detect status changes of a contact, and retrieve your buddylist from an ICQ server
BuddySpace is an enhanced Jabber client providing secure presence management, web services and instant messaging. It extends the 'buddy list' concept with enhanced and customisable visualisation of presence (incl. maps, logical layouts).
Chat Everywhere aims to be a simple but powerful chat server (minor footprint, no software to install on the client side, Apache-like config file, extended config options, out-of-the-box running server, irc-like commands, 10 level of hierarchy, etc.
provides a friendly client application that covers the needs of users who use Blogger.com for all of their journalling needs
(commercial) a complete instant messaging server that can be easily integrated in any Java / J2EE application
GOIM (Gamers Own Instant Messenger) is a full featured jabber / XMPP client with special features (extensions) for gamers. (e.g. broadcasting a notification when you join a server, or seeing which games others play and joining them with one click on the game icon beside their name).
goText is a program for Java mobile phones that allows you to send text messages over GPRS/EDGE/UMTS.
Gozirra (formerly SERStomp) is a lightweight client and server implementation of the Stomp (TTMP) protocol, implemented in Java. The main goal of SERStomp is to provide a tiny embeddable library that applications can use as a simple messaging provider. Stomp is a simple, lightweight publish/subscribe messaging protocol.
HL7 Comm is a stand-alone integration tool written in Java that allows you to send and receive HL7 messages over a TCP/IP MLLP connection. It offers a simple mode for testing and a configured mode for running as a full-fledged integration client, either with or without a GUI interface.
a set Ant tasks for sending Instant Message notifications. Currently supporting AIM, Jabber (& Secure Jabber), Yahoo!, and MSN Messenger
Ivy software bus
a simple protocol and a set of libraries that allows applications to broadcast information through text messages, with a subscription mechanism based on regular expressions.
Java AIM Bot
a modular architecture for providing services through an AIM client
JBother is a Jabber client written in pure Java (1.4.x). It supports groupchat in a tabbed window, multiple resources, transport registration (so you can get on AIM, MSN, Yahoo!, and ICQ through JBother), sounds for different events, has several different skins, and should run on any platform that has the JRE installed.
JClaim is an instant message client, tools, and development framework. It supports AIM, ICQ, Yahoo!, MSN, Jabber, and SMS. The framework can be used for designing your own tools.
jcq2k is an open source LGPL reusable instant messaging plugin utilizing the TCP-based ICQ2000 OSCAR protocol implemented in Java.
a messaging system that partially implements the Java Messaging Service (JMS) API. JMS4Spread utilizes the Spread toolkit for high performance messaging that is resilient to faults across external or internal networks
Java (TM) Open Reliable Asynchronous Messaging
myJCQ is a implementation of the ICQ Oscar Protocol in Java.
OpenIM is a fast, simple, and highly efficient instant messager server with high modularisation and a codebase that uses the Avalon tools and Merlin Container created by Apache's Avalon project.
(commercial) Ponton X/P is an ebXML/AS1/AS2 Message Service that is currently in use at over 80 companies in Europe and North America. Ponton X/P is used to validate, sign, encrypt, archive, and exchange documents between businesses via HTTP(S) or email.
Praya is a unified, flexible, extendable, simple, universal messaging client.
QuickFIX/J is an implementation of the FIX (Financial InterXchange) protocol based on the popular C++ version of the engine.
Spark is a free, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great end-user experience with features like in-line spell checking, group chat room bookmarks, and tabbed conversations.
a client-based proxy for AOL Instant Messenger communication. Arbitrary connections can be made between screen names, two users can be piped together, and messages may be sent to users
TiVonage allows Vonage customers to use a TiVo to manage their voice mail, including checking for new messages, listening to messages, viewing caller ID and address info, and returning calls via Click2Call.
Tulka Whiteboard is a communication tool which allows you to share a whiteboard between several people. The whiteboard can be accessed by a simple web interface. All that the participant need is a web browser with Java support.
zLogFabric is an all in one cross-platform logging solution that collects log lines/messages over a messaging system to a central server instance.