What does the strictfp keyword do?

The keyword strictfp allows you to have more (predictable) control over floating-point arithmetic. It may be used (as a modifier) to classes, interfaces and methods. If a floating point expression is within a strictfp “scope”, the results will be as predictable as described in IEEE 754 (see link below). If the expression is not FP-strict, the specification is more tolerant and the result is determined by the extra precision bits that may be used in evaluating the expression (extended exponent range implemented by the VM being used).
Check out the other link below (Changes to the Java Language Specification).