How to Convert all LinkedHashMap Values to a List in Java?

Last Updated : 19 Sep, 2022

The task is to convert all LinkedHashMap values to a list in java. LinkedHashMap is an implementation of a Map. The Map and List are two different data structures. The Map stores key-value pairs while the List is an ordered collection of elements.

To convert all values of the LinkedHashMap to a List using the values() method. The values() method of the LinkedHashMap class returns a Collection view of all the values contained in the map object. You can then use this collection to convert it to a List object.

Syntax:

LinkedHashMap.values()

Return Value: The method is used to return a collection view containing all the values of the map.

Example 1:

Java

// Java program to Convert all LinkedHashMap values to a
// List

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

public class LinkedHashMapToListExample {

    public static void main(String[] args)
    {

        // instance of linkedhashmap
        LinkedHashMap<Integer, Integer> lhmap
            = new LinkedHashMap<Integer, Integer>();

        // add mappings
        lhmap.put(1, 11);
        lhmap.put(2, 22);
        lhmap.put(3, 33);

        // convert values to a list
        List<Integer> listValues
            = new ArrayList<Integer>(lhmap.values());

        // print values
        System.out.println("List contains:");
        for (Integer value : listValues) {
            System.out.println(value);
        }
    }
}

Output

List contains:
11
22
33

Example 2:

Java

// Java program to Convert all LinkedHashMap values to a
// List

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

public class LinkedHashMapToListExample {

    public static void main(String[] args)
    {

        // instance of linkedhashmap
        LinkedHashMap<Integer, String> lhmap
            = new LinkedHashMap<Integer, String>();

        // add mappings
        lhmap.put(10, "Geeks");
        lhmap.put(15, "4");
        lhmap.put(20, "Geeks");
        lhmap.put(25, "Welcomes");
        lhmap.put(30, "You");

        // convert values to a list
        List<String> listValues
            = new ArrayList<String>(lhmap.values());

        // print values
        System.out.println("List contains:");
        for (String value : listValues) {
            System.out.println(value);
        }
    }
}

Output

List contains:
Geeks
4
Geeks
Welcomes
You

Another Method : Using List.copyOf()

In java, we can convert the set to list by using List.copyOf(object). For this, we have to import the package java.util.List.*. It is a static factory method which creates the list object from another collection or object.