How to Shuffle or Randomize a list in Java

In this tutorial, we’re going to see how to Shuffle or Randomize a list in Java, here is the utility method Collections.shuffle().

This method does not create a new list, but modify the passed list:

import java.util.*;

public class Main
{
     public static void main(String []args)
     {
        List<String> list = Arrays.asList("Alex", "Emily", "Jean", "Bob");
        Collections.shuffle(list);
        System.out.println(list);
     }
}

Output:

[Emily, Alex, Bob, Jean]

 
In a second version of this method, the random generator can be specified:

import java.util.*;
import java.security.SecureRandom;

public class Main
{
     public static void main(String []args)
     {
        List<String> list = Arrays.asList("Alex", "Emily", "Jean", "Bob");
        SecureRandom random = new SecureRandom();
        Collections.shuffle(list, random);
        System.out.println(list);
     }
}

Output:

[Alex, Bob, Emily, Jean]

In the default implementation the random generator is java.util.Random.
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