Java: Count the number of key-value (size) mappings in a map

Last update on March 12 2025 13:34:14 (UTC/GMT +8 hours)

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

Sample Solution:-

Java Code:

import java.util.*;  
public class Example2 {  
   public static void main(String args[]){  
  HashMap<Integer,String> hash_map= new HashMap<Integer,String>();  
  hash_map.put(1, "Red");
  hash_map.put(2, "Green");
  hash_map.put(3, "Black");
  hash_map.put(4, "White");
  hash_map.put(5, "Blue");
  System.out.println("Size of the hash map: "+hash_map.size());
 }
}

Sample Output:

Size of the hash map: 5 

For more Practice: Solve these Related Problems:

• Write a Java program to calculate the size of a HashMap after bulk insertion and deletion operations.
• Write a Java program to compare the size of two maps and print the one with the greater number of mappings.
• Write a Java program to use Java streams to count and print the total number of key-value pairs in a map.
• Write a Java program to create a method that returns the size of a map and then verifies it by iterating over the map entries.

Java Code Editor:

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