Not sure why the old one was replaced. Anyway:

http://www.pjirc.com - Free, demo included. The only java IRC client I could find on download.com that's 100% free. Unne might be pleased that it is indeed open source material. Doubt he'll care though because he's one of those "I've never gone to chat and never will" people.

Listed features:
- Highlight support
- ASL handling
- Graphical bitmap used for smiley’s
- Nickname auto completion
- Nick, channel and URL catcher
- Sound support
- Multilingual support
- Esthetical options such as background image, per-channel color configuration, and so on…
- UTF-8 encoding support
- Support for external control via javascript
- “On connect” command list
- Time stamping
- Fast, light and reliable
- Free and open source


Whee. Good enough for me. I'm sure we can disable stuff we don't need, anyway. The only thing that really mattered was it not requiring registration or anything dumb like that, since it's free and all - now, someone check out the demo because I'm at work and can't.