why don't do a pure java chat software? who needs html rendering for a chat? the main feature is
a) waiting for customers to enter
b) chatting...
i did something like that one year ago for a social networking plattform, where i could not get the raw data or do any db-queries. i had to fake http request and however it worked pretty well. but this one is pretty straight forward if you do implement only the basic features. i did my user interface with a slightly customized jxtaskpane/-container..
edit: ahh.. i just looked at your windows app (its russian by default?!). now i know what you want. thats pretty simple. you just make a watchdog which polls the db for incoming chats and when a new request comes in, the app could play sound, show a ballon text and open the default browser.
1. you can open a url in the default browser with java.awt.Desktop (since java 6). use the browse()-funktion for that.
2. for ballon texts and tray-icon use jdic (needs platform-dependent port of the library which is BAD).
https://jdic.dev.java.net/3. if you really want to embed a browser like internet explorer into your java app use jdic, too. there is support for simple html in jeditorpane, too. both would be more than BAD.
anyway, i would consider a real app which implements the basic functionality on its own way more interessting. if i had some time... ;-)