java.util.Collections.singletonList() Method

---

Description

The singletonList(T) method is used to return an immutable list containing only the specified object.

Declaration

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

public static <T> List<T> singletonList(T o)

Parameters

o − This is the sole object to be stored in the returned list.

Return Value

• The method call returns an immutable list containing only the specified object.

Exception

NA

Example

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

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);

      // create singleton list
      list = Collections.singletonList("TP");

      System.out.println("List value after: "+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: [TP]