java.util.Collections.sort() Method

---

Description

The sort(List<T>) method is used to sort the specified list into ascending order, according to the natural ordering of its element.

Declaration

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

public static <T extends Comparable<? super T>> void sort(List<T> list)

Parameters

list − This is the list to be sorted.

Return Value

NA

Exception

• ClassCastException − Throws if the list contains elements that are not mutually comparable (for example, strings and integers).

• UnsupportedOperationException − Throws if the specified list's list-iterator does not support the set operation.

Example

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

package com.tutorialspoint;

import java.util.*;

public class CollectionsDemo {
   public static void main(String args[]) {

      // create an array of string objs
      String init[] = { "One", "Two", "Three", "One", "Two", "Three" };

      // create one list
      List list = new ArrayList(Arrays.asList(init));

      System.out.println("List value before: "+list);

      // sort the list
      Collections.sort(list);

      System.out.println("List value after sort: "+list);
   }
}

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

List value before: [One, Two, Three, One, Two, Three]
List value after sort: [One, One, Three, Three, Two, Two]