With this example we are going to demonstrate how to get the size of a HashMap, that is the number of key value pairs that the HashMap contains. In short, to the size of a HashMap you should:
- Create a new HashMap.
- Populate the hashMap with elements, with the
put(K key, V value)API method of HashMap. - Invoke the
size()API method of the HashMap. It will return the int number of key value pairs stored in the hashMap.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
import java.util.HashMap;
public class SizeHashMap {
public static void main(String[] args) {
// Create a HashMap and populate it with elements
HashMap hashMap = new HashMap();
hashMap.put("key_1","value_1");
hashMap.put("key_2","value_2");
hashMap.put("key_3","value_3");
// int size() operation returns the number of key value pairs stored in HashMap
System.out.println("Size of HashMap : " + hashMap.size());
}
}
Output:
Size of HashMap : 3
This was an example of how to the size of a HashMap in Java.
