In Java, a HashMap is a commonly used data structure that stores key-value pairs. It allows for efficient retrieval and insertion of elements, making it ideal for many applications. Here is the syntax for creating a HashMap in Java:

// Import the HashMap class
import java.util.HashMap;

// Create a new HashMap object
HashMap<KeyType, ValueType> hashMapName = new HashMap<>();

Let’s break down the above syntax:

• First, we import the HashMap class from the java.util package.
• Next, we declare and initialize a new HashMap object named hashMapName.
• Inside the angle brackets (<>), you need to specify the types of the key and value that the HashMap will hold. Replace KeyType with the type of your key and ValueType with the type of your value.

For example, if you want to create a HashMap with keys of type String and values of type Integer, you would use the following syntax:

HashMap<String, Integer> hashMapName = new HashMap<>();

You can then add key-value pairs to the HashMap using the put() method:

hashMapName.put("key1", 123);
hashMapName.put("key2", 456);

To access the value associated with a specific key, you can use the get() method:

Integer value = hashMapName.get("key1");

The HashMap class in Java provides various other methods for manipulating and iterating over the elements it contains. You can refer to the official Java documentation for HashMap for more details.

Remember to import the java.util.HashMap class at the start of your Java file to use HashMap in your code.

Hashtags: #Java #HashMap