Java strictfp keyword example

In Java, the strictfp keyword is used to force the precision of floating point calculations (float or double) in Java conform to IEEE’s 754 standard, explicitly. Without using strictfp keyword, the floating point precision depends on target platform’s hardware, i.e. CPU’s floating point processing capability. In other words, using strictfp ensures result of floating point computations is always same on all platforms.

The strictfp keyword can be applied for classes, interfaces and methods.

Some Rules about strictfp:

• •           strictfp cannot be applied for constructors.
  •          If an interface or class is declared with strictfp, then all methods and nested types within that interface or class are implicitly strictfp.
  •           strictfp cannot be applied for interface methods.

Java strictfp keyword Examples:

The following class is declared with strictfp, hence all the floating point computations within that class conform to IEEE’s 754 standard:

strictfp class StrictFPClass {
    double num1 = 10e+102;
    double num2 = 6e+08;
    double calculate() {
        return num1 + num2;
    }
} 

The following interface is declared with strictfp, but its methods cannot:

strictfp interface StrictFPInterface {
    double calculate();
    strictfp double compute();    // compile error
} 

The following method is declared with strictfp:

class StrictFPMethod {
    strictfp double computeTotal(double x, double y) {
        return x + y;
    }
}

See all keywords in Java.

Other Recommended Tutorials:

• 9 Rules about Constructors in Java
• 12 Rules and Examples About Inheritance in Java
• 12 Rules of Overriding in Java You Should Know
• 10 Java Core Best Practices Every Java Programmer Should Know
• Understand Interfaces in Java
• Understand how variables are passed in Java
• Understand encapsulation in Java

About the Author:

Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He began programming with Java back in the days of Java 1.4 and has been passionate about it ever since. You can connect with him on Facebook and watch his Java videos on YouTube.