HashMap is a commonly used data structure in Java that stores elements in key-value pairs. In this blog post, we will explore how to add elements to a HashMap in Java.

Table of Contents

• What is a HashMap?
• Adding Elements to a HashMap
• Example Code
• Conclusion

What is a HashMap?

A HashMap in Java is an implementation of the Map interface that allows you to store a collection of key-value pairs. It uses hashing techniques to store and retrieve elements efficiently.

Adding Elements to a HashMap

To add elements to a HashMap in Java, you need to use the put() method. The put() method allows you to insert a key-value pair into the HashMap. If the key already exists in the HashMap, the value associated with that key will be updated.

Here’s the syntax for adding elements to a HashMap:

map.put(key, value);

Where map is the reference to the HashMap, key is the unique identifier for the element, and value is the actual element you want to add.

It’s important to note that the key in a HashMap should be unique. If you try to add a duplicate key, the existing value will be overwritten.

Example Code

Let’s see an example of how to add elements to a HashMap in Java:

import java.util.HashMap;
  
public class HashMapExample {
    public static void main(String[] args) {
        // Create a new HashMap
        HashMap<String, Integer> map = new HashMap<>();

        // Add elements to the HashMap
        map.put("apple", 1);
        map.put("banana", 2);
        map.put("orange", 3);

        // Print the HashMap
        System.out.println(map);
    }
}

In this example, we create a HashMap and add three elements to it. The keys are strings (“apple”, “banana”, “orange”) and the values are integers (1, 2, 3). Finally, we print the HashMap to verify the elements have been added successfully.

Conclusion

Adding elements to a HashMap in Java is straightforward using the put() method. Remember to use unique keys to avoid overwriting existing values. HashMaps are a powerful data structure in Java, allowing efficient storage and retrieval of key-value pairs.

Give it a try and explore more functionalities of the HashMap class in Java. Happy coding! #Java #HashMap