java.util.Collections.rotate() Method

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Description

The rotate(List<?>, int) method is used to rotate the elements in the specified list by the specified distance.

Declaration

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

public static void rotate(List<?> list,int distance)

Parameters

• list − This is the list to be rotated.

• distance − This is the distance to rotate the list.

Return Value

NA

Exception

UnsupportedOperationException − This is thrown 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.rotate()

package com.tutorialspoint;

import java.util.*;

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

      // populate the list
      for (int i = 0; i < 15; i++) {
         numbers.add(i);
      }

      System.out.println("Before : "+Arrays.toString(numbers.toArray()));

      // rotate the list at distance 10
      Collections.rotate(numbers, 10);

      System.out.println("After : "+Arrays.toString(numbers.toArray()));
   }
}

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

Before : [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
After : [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 1, 2, 3, 4]