Using java.util.Random class we can create random data such as boolean, integer, floats, double. First you’ll need to create an instance of the Random class. This class have some next***() methods that can randomly create the data.

package org.kodejava.example.util;

import java.util.Arrays;
import java.util.Random;

public class RandomDemo {
    public static void main(String[] args) {
        Random r = new Random();

        // generate some random boolean values
        boolean[] booleans = new boolean[10];
        for (int i = 0; i < booleans.length; i++) {
            booleans[i] = r.nextBoolean();
        }
        System.out.println(Arrays.toString(booleans));

        // generate a uniformly distributed int random numbers
        int[] integers = new int[10];
        for (int i = 0; i < integers.length; i++) {
            integers[i] = r.nextInt();
        }
        System.out.println(Arrays.toString(integers));

        // generate a uniformly distributed float random numbers
        float[] floats = new float[10];
        for (int i = 0; i < floats.length; i++) {
            floats[i] = r.nextFloat();
        }
        System.out.println(Arrays.toString(floats));

        // generate a Gaussian normally distributed random numbers
        double[] doubles = new double[10];
        for (int i = 0; i < doubles.length; i++) {
            doubles[i] = r.nextGaussian();
        }
        System.out.println(Arrays.toString(doubles));
    }
}

The result of the code snippet above are:

[true, false, false, true, true, true, true, false, false, true]
[880569018, 584161271, 1188257744, 1810736813, 2065540711, 2129338546, 1939490062, 1865141839, -1660461645, 211673120]
[0.097299635, 0.44844186, 0.5900976, 0.43893605, 0.8813426, 0.71923894, 0.7685699, 0.19013077, 0.8173217, 0.3595813]
[-0.037493646212294, 1.756568052729634, 0.8849071468575704, -0.27909848975272716, 1.7014373967099943, 0.7562137933093157, -1.2515831815175729, 0.8055530429393517, -0.10414001279168857, 1.347637572163826]

For an example to create random number using the Math.random() method see How do I create random number?.

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Wayan

Programmer, runner, recreational diver, live in the island of Bali, Indonesia. Mostly programming in Java, Spring Framework, Hibernate / JPA.

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