Java Math random() Method

The random() method of Math class returns a double value with a positive sign, less than 1 and greater than or equal to 0.0. This method is properly synchronized with the correct use of one or more thread.

Syntax:

public static double random ()

Return Value:

The random() method returns a pseudorandom double value less than 1 and greater than or equal to 0.0.

Example 1:

public class JavaMathRandomExample1 {
    static int i=1;
    public static void main(String[] args) {
        // generate random number
        double a = Math.random();
        double b = Math.random();
        // Output generated is random and different for every code
        System.out.println(i++ +". Random value : "+ a);
        System.out.println(i++ +". Random value : "+b);
    }
}

Output:

Random value : 0.5940972537310859
Random value : 0.07044302938090907

Example 2:

public class JavaMathRandomExample2 {
    static int i=1;
    public static void main(String[] args) {
        // generate random number
        double a = Math.random()*Double.NaN;
        // Output generated will be NaN
        System.out.println(i++ +". Random value : "+ a);
    }
}

Output:

Random value : NaN

Example 3:

public class JavaMathRandomExample3 {
    static int i=1;
    public static void main(String[] args) {
        // generate random number
        double a = Math.random()*Double.POSITIVE_INFINITY;
        // Output generated will be infinity
        System.out.println(i++ +". Random value : "+ a);
    }
}

Output:

Random value : Infinity

Example 4:

public class JavaMathRandomExample4 {
    static int i=1;
    public static void main(String[] args) {
        // generate random number
        double a = Math.random()/Double.NEGATIVE_INFINITY;
        // Output generated will be -0.0
        System.out.println(i++ +". Random value : "+ a);
    }
}

Output:

Random value : -0.0