java.util.Collections.singletonList() Method


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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]

java_util_collections.htm

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