Bug Tracking Java
You have found the way to Java on Bug Tracking:
Agility - A customizable Issue and Bug tracking solution. It comes in both a Hosted model and a more traditional Enterprise model. [Commercial]
BugRat - A bug reporting and tracking system. [Open source]
bugTracker - Defect tracking solution written entirely in Java. [Open source, Apache-style license]
Bugzero - Web-based bug/defect/issue/incident tracking software and change management system written in Java servlet (J2EE) and database technologies. By WEBsina. [Shareware]
GRAN PM - Java-based scalable and customizable bug tracking software. Supports workflow, PDF reports with charts, and multi-level security. By GRAN Ltd. [Commercial]
JIRA - Innovative, browser-based J2EE defect tracking and issue management tool. By Atlassian Software Systems. [Shareware]
Ozibug - Web based bug tracking system, written entirely in Java and utilizing servlet technology. By Tortuga Technologies. [Shareware]
Scarab - Servlet-based issue tracker - replacement for Bugzilla. [Open Source, BSD-like]
TrackStudio - Servlet-based issue tracking and project management software. Multi-level security, workflow, reports. [Shareware]
WorkRoll Bug Tracker - A web-based bug tracker, runs under any Servlets 2.2-compatible application server. No non-standard packages required; no database required. Installation, configuration, day-to-day administration, and general use are fully web-based. Help build the largest human-edited directory on the web.