Get Size of Java HashMap Example

This Java Example shows how to get the size or nubmer of key value pairs stored in HashMap using size method.

import java.util.HashMap;

public class GetSizeOfHashMapExample {

 public static void main(String[] args) {

  // create HashMap object
  HashMap hMap = new HashMap();

  /**
   * To get the size of HashMap use int size() method of HashMap class. It
   * returns the number of key value pairs stored in HashMap object.
   **/
  System.out.println("Size of HashMap : " + hMap.size());

  // add key value pairs to HashMap using put method
  hMap.put("1", "One");
  hMap.put("2", "Two");
  hMap.put("3", "Three");

  System.out.println("Size of HashMap after addition : " + hMap.size());

  // remove one element from HashMap using remove method
  Object obj = hMap.remove("2");

  System.out.println("Size of HashMap after removal : " + hMap.size());
 }
}

The output is:



Size of HashMap : 0
Size of HashMap after addition : 3
Size of HashMap after removal : 2