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Java program to check whether a HashMap contains a specified Key or not

Given a HashMap collection, we have to check whether it contains a specified Key or not.
Submitted by Nidhi, on June 10, 2022

Problem statement

In this program, we will create a collection of key/value pair information using the HashMap collection. Then we will check whether a specified key exists in created HashMap or not using the containsKey() method.

Java program to check whether a HashMap contains a specified Key or not

The source code to check whether a HashMap contains a specified Key or not is given below. The given program is compiled and executed successfully.

// Java program to check whether a HashMap contains 
// a specified Key or not

import java.util.*;

public class Main {
  public static void main(String[] args) {
    HashMap < Integer, String > emp = new HashMap < > ();

    emp.put(101, "Amit");
    emp.put(102, "Arun");
    emp.put(103, "Akas");
    emp.put(104, "Ram");
    emp.put(105, "Mohan");

    if (emp.containsKey(103))
      System.out.println("Key 103 is contained in 'emp' HashMap.");
    else
      System.out.println("Key 103 is not contained in 'emp' HashMap.");

    if (emp.containsKey(107))
      System.out.println("Key 105 is contained in 'emp' HashMap.");
    else
      System.out.println("Key 105 is not contained in 'emp' HashMap.");
  }
}

Output

Key 103 is contained in 'emp' HashMap.
Key 105 is not contained in 'emp' HashMap.

Explanation

In the above program, we imported the "java.util.*" package to use the HashMap class. Here, we created a public class Main.

The Main class contains a main() method. The main() method is the entry point for the program. And, created an object of the HashMap class and store the employee information using the put() method. Then we checked whether the specified key exists in HashMap or not using the containsKey() method and printed the appropriate message.

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