Collections.singleton(List) in Java

Collections.singleton(List): This method is available in java.util.Collections class of Java.

Syntax:

<List<E>> Set<List<E>> java.util.Collections.singleton(List<E> o)

This method takes one argument. This method returns an immutable set containing only the specified object.The returned set is serializable.

Parameters: One parameter is required for this method.

o: the sole object to be stored in the returned set.

Returns: an immutable set containing only the specified object.

Exceptions: NA

Approach

Java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

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

        List<Integer> arrlist = new ArrayList<Integer>();

        arrlist.add(12);
        arrlist.add(56);
        arrlist.add(899);
        arrlist.add(65);
        arrlist.add(12);

        System.out.println(Collections.singleton(arrlist));

    }
}

Output:

[[12, 56, 899, 65, 12]]