PircBot

http://www.jibble.org/pircbot.php

Java IRC API

PircBot is a Java framework for writing IRC bots quickly and easily. Its features include an event-driven architecture to handle common IRC events, flood protection, DCC resuming support, ident support, and more. Its comprehensive logfile format is suitable for use with pisg to generate channel statistics. Full documentation is included, and this page contains a 5-minute step-by-step guide to making your first IRC bot.