The most complete fuzzy logic library in Java. The de-facto standard for research and industrial applications.
See description, manual and examples here: http://jfuzzylogic.sourceforge.net
2022/05/26:
New feature: FCL compiler (JavaScript) + some bug fixes + make charts resizable - by Marcin Szczepański (Faculty of Mathematics and Computer Science, Adam Mickiewicz University, Poznan, Poland)