what programming language is mozilla firefox written in

No accelerated graphics is also a big negative here. Have you ever tried to build a UI with Java? It feels cumbersome and slow compared to anything else out there, because it is. So there really is no clear winner in this area. Both Java and C# have non-blocking IO support, as does C++. The raw speed of the wire is the limiting factor. The reason is that communication is many times slower than the rest of the processing that goes on to display the page. Networking is actually the least of the reasons to choose C++ over Java or C#. WPF on C# provides access to accelerated graphics, but it is too new to have a serious browser built with the technology. Accessing accelerated graphics in Java is a no go, unless you have some native extensions to make it work. However, C and C++ have quite a few years head start on the rest of the alternatives so the algorithms and implementations are more mature. You have parser generators for C, C++, C#, Java, etc. Most languages have some sort of parsing support. For the more advanced browsers: control over processes and isolating memory between pages.Tree walking/interpreting features (part of parsing and building UI).Support for parsing (needed to make sense of HTML, CSS, and Script).Another way to ask the question is what kind of support does a browser need? The short list is:

What programming language is mozilla firefox written in