fuzzylite is a cross-platform, free and open-source fuzzy logic control library programmed in C++. Its goal is to allow you to easily create fuzzy logic controllers in a few steps utilizing object-oriented programming without requiring any third-party libraries.
jfuzzylite is the same fuzzylite library, but programmed entirely in Java without requiring any third-party libraries.
qtfuzzylite is a cross-platform, free and open-source Qt-based graphic user interface for fuzzylite. Its goal is to allow you to visually design your fuzzy logic controllers and interact with them in real time.