Here's a workaround on chrome, I'm on mac but this should still work on PC:
1: Go to the chat room page where it says "This software requires java/get java now"
2: Right click, hit "inspect".
3: On the window that pops up, locate the "toggle device toolbar" button. It looks like a generic iphone device in front of a generic tablet device. Click the button. This should shrink the page you see, and essentially trick chrome into thinking you're on a mobile device.
4: Hit refresh then enter your username and password.
5: Click "enter chatroom". A new window should pop up with the chatroom in it's mobile form. You can close the old window. Voila!