How to check if a key exists in a HashMap in Java

In this tutorial, we are going to see how to check if a key exists in a HashMap in Java. In Java, you can use Map.containsKey() method to check if a key exists in a HashMap in Java.
 

Java Program to check if a key exists in a HashMap:

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Map<Integer, String> lang = new HashMap<>();
        lang.put(1, "Java");
        lang.put(2, "PHP");
        lang.put(3, "Python");
        lang.put(4, "C++");

        if (lang.containsKey(3)) {
            System.out.println("The key exists and, its value is "+ lang.get(3));
        } else {
            System.out.println("The key does not exist!");
        }
    }
}

Output:

The key exists and, its value is Python

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