java.util.Collections.shuffle() Method

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Description

The shuffle(List<?>) method is used to randomly permute the specified list using a default source of randomness.

Declaration

Following is the declaration for java.util.Collections.shuffle() method.

public static void shuffle(List<?> list)

Parameters

list − The list to be shuffled.

Return Value

NA

Exception

UnsupportedOperationException − Throws if the specified list or its list-iterator does not support the set operation.

Example

The following example shows the usage of java.util.Collections.shuffle()

package com.tutorialspoint;

import java.util.*;

public class CollectionsDemo {
   public static void main(String args[]) {
      
      // create array list object       
      List arrlist = new ArrayList();

      // populate the list
      arrlist.add("A");
      arrlist.add("B");
      arrlist.add("C");  

      System.out.println("Initial collection: "+arrlist);

      // shuffle the list
      Collections.shuffle(arrlist);

      System.out.println("Final collection after shuffle: "+arrlist);
   }    
} 

Let us compile and run the above program, this will produce the following result.

Initial collection: [A, B, C]
Final collection after shuffle: [C, A, B]