Strictfp is a keyword and can be used to modify a class or a method, but never a variable. Marking a class as strictfp means that any method code in the class will conform to the IEEE 754 standard rules for floating points. Without that modifier, floating points used in the methods might behave in a platform-dependent way. If you don't declare a class as strictfp, you can still get strictfp behaviour on a method-by-method basis, by declaring a method as strictfp. If you don't know the IEEE 754 standard.