The Java Technologies Behind the New Developer Forums - By Dana Nourie. This article focuses on the Java technologies used in the general architecture of Jive forums, as well as the configurations and changes to code for the Jive special forum features. - http://java.sun.com/developer/technicalArticles/javaopensource/jive/
Yazd - Java based forum software, with three different skins. [Open source, Apache License] - http://www.forumsoftware.ca
Meinds - Java based messaging and information database system. [Open source] - http://meinds.sourceforge.net/
eForum - Enables geographically distant participants to share ideas and enhance teamwork via the Web. Supports moderation and email notifications. [Open Source, BSD-like] - http://www.jcorporate.com/econtent/Content.do;jsessionid=aaa7LxxireKymd19UfOg?state=template&template=2&db=default&resource=642
mvnForum - A bulletin board (forum) built on the J2EE technology(Jsp/Servlet). mvnForum is compatible with any Servlet Container which supports Jsp 1.1 and Servlet 2.2. [Open source, GPL] - http://mvnForum.com
Jive Forums - A highly configurable and extensible web forum software, written in Java. [Shareware] - http://www.jivesoftware.com/