Write a Java program to count the number of key-value (size) mappings in a map

This is a Java program that demonstrates how to count the number of key-value pairs in a HashMap. Here's how it works:

First, a HashMap object is created using the HashMap class. This specifies that the keys in the HashMap will be of type Integer, while the values will be of type String.
Next, key-value pairs are added to the HashMap using the put() method. In this example, we add five pairs, with keys ranging from 1 to 5, and string values representing different types of fruits.
Finally, the size() method is used to get the number of key-value pairs in the HashMap, which is then printed to the console.

Source Code

import java.util.*;  
public class CountNum_KeyValue
{  
	public static void main(String args[])
	{  
		HashMap<Integer,String> hash_map = new HashMap<Integer,String>();  
		hash_map.put(1, "Cherry");
		hash_map.put(2, "Banana");
		hash_map.put(3, "Apple");
		hash_map.put(4, "Mango");
		hash_map.put(5, "Guava");
		System.out.println("Count Number of Key-Value in HashMap : "+hash_map.size());
	}
}

Output

Count Number of Key-Value in HashMap : 5

Write a Java program to count the number of key-value (size) mappings in a map

Source Code

Output

Example Programs

HashMap Programs in Java