This application written in C++ and assembly runs on millions of PCs, has been around for over a dozen years, is open source and you will most likely use it everyday although not directly.
It's the HotSpot JVM that runs Java code on desktops and servers. Note that url seems to be down at the moment but Google has a recent cached copy. It's called HotSpot because it looks for hot spots to optimize execution in a Java application.
- Permanent Link added to C++ Code Library