Java: How to Add two Maps with example

If you have two or more Map collections in Java and you want to add them, make use of there putAll method.

package org.code2care.java.collection.examples;

import java.util.HashMap;
import java.util.Map;

/**
 * Example: Add two Maps
 *
 * Author: Code2care.org
 * Date: 3nd May 2023
 * Version: v1.0
 *
 */
public class CombineMapsJava {

    public static void main(String[] args) {

        Map<String, Integer> countriesMap1 = new HashMap<>();
        countriesMap1.put("China", 1);
        countriesMap1.put("Japan", 2);

        Map<String, Integer> countriesMap2 = new HashMap<>();
        countriesMap2.put("Canada", 3);
        countriesMap2.put("USA", 4);

        Map<String, Integer> countriesMap = new HashMap<>();
        countriesMap.putAll(countriesMap1);
        countriesMap.putAll(countriesMap2);

        System.out.println(countriesMap);

    }
}