How To Create an Empty Map in Java

Creating an Empty Map in Java

A Map is a collection of key-value pairs. In Java, Maps are used to store data in key-value pairs and can be used to quickly look up values associated with a given key. Java provides several implementations of Map, the most commonly used being HashMap.

In this tutorial, we'll learn how to create an empty Map in Java. We'll also discuss different methods to add and retrieve elements from an Empty Map.

Creating an Empty Map in Java

The simplest way to create an empty Map in Java is to use the constructor provided by the Map interface. The following code snippet shows how to create an empty Map using the Map constructor.

Map<String, Integer> emptyMap = new HashMap<>();

The above code creates an empty Map that can store objects of type String as keys and Integer as values.

Adding Elements to an Empty Map in Java

Once you have an empty Map, you can add elements to the Map using the put() method provided by the Map interface. The following code snippet shows how to add elements to an empty Map in Java.

emptyMap.put("key1", 1);
emptyMap.put("key2", 2);

The above code adds two elements to the empty Map created earlier. The first element is a key-value pair with key “key1” and value 1. The second element is a key-value pair with key “key2” and value 2.

Retrieving Elements from an Empty Map in Java

Once you have populated an empty Map with elements, you can retrieve them using the get() method provided by the Map interface. The following code snippet shows how to retrieve elements from an empty Map in Java.

Integer value1 = emptyMap.get("key1");
Integer value2 = emptyMap.get("key2");

The above code retrieves the values stored for the keys “key1” and “key2”. The variable value1 will contain the value 1 and the variable value2 will contain the value 2.

Conclusion

In this tutorial, we learned how to create an empty Map in Java, add elements to it, and retrieve elements from it. Maps are incredibly useful data structures and are often used to store data in key-value pairs. Knowing how to work with Maps in Java is an important skill for any Java developer.