AlarmJ is an adequate but feature-poor countdown timer for intervals up to 90 minutes. It requires no installation and runs in a small, nonresizable window. Its minimalist interface makes it very simple to set the timer and choose from among the four available alarm sounds. Once the time expires, it will play the alert sound continuously until you press the Stop button. You can pause the timer anytime you want.
Unlike similar apps, AlarmJ doesn't have a minimize option to run on the system tray. You can't set reminders for yourself as time expires. You can't use your own audio files, nor can you set multiple timers. It's light on bells and whistles, but if you're looking for a free, simple timer, AlarmJ will do the trick.