I am a Java developer, and I rarely write GUI program in C. However, I noticed that many GNU's projects, such as PSPP, R, Dia, etc., are written in C, instead of Java or C++. I personally don't mind this, but I am really curious why GNU favors C so much. My understanding is that C is the one that supports the least in object-oriented programming, and today's CS education really emphasizes OOP, as OOP really makes codes more reusable. In this case, why would so many developers choose to develop in C instead of C++ or Java. Does anyone know why GNU's software are so exclusively written in C? Do you think or GNU's software should be written in C++ or Java so that the source code could be more useful to people? Why or why not?