A while ago I experimented with writing a program to simulate the behaviour of Cisco switches and Routers, with the idea of embedding it in a webpage so that it could be accessed for free using any web browser. This application would need to be rather complex, and could have been quite processor intensive, so I chose to write the application using java as this could also be easily embedded in a webpage. Nowadays java is very unpopular for such purposes, and most web browsers impose restrictions on java applications which simply make it too hard for end users. I decided that for this program to be of any use I would need to find another method to allow this to run inside a web browser.
It seemed that the most compatible method would be to rewrite the program in javascript, but this was simply not an option due to the huge effort involved, and that I could not bear to even think about writing a large OO program in javascript. I soon stumbled across a development toolkit made by Google, called GWT (Google Web Toolkit). This was exactly what I needed! GWT allows code to be written in Java, and then compiled into javascript which can be used in a webpage.
In order to use GWT I did need to make some changes to the original program, mostly user interface related. One great thing with GWT is that it allowed me to use Eclipse for development, and also allows debugging which could be difficult if writing entirely in javascript.
You can check out this simulator at http://www.net-refresh.com.
Steve Harvey 
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