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Java HashMap size() Method with Example

HashMap Class size() method: Here, we are going to learn about the size() method of HashMap Class with its syntax and example.
Submitted by Preeti Jain, on March 04, 2020

HashMap Class size() method

• size() method is available in java.util package.
• size() method is used to return the size (i.e. the number of key-value pairs exists) of this HashMap.
• size() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• size() method does not throw an exception at the time of returning size.

Syntax:

    public int size();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is int, it returns this HashMap size.

Example:

// Java program to demonstrate the example 
// of int size() method of HashMap 

import java.util.*;

public class SizeOfHashMap {
    public static void main(String[] args) {
        // Instantiates a HashMap object
        Map < Integer, String > map = new HashMap < Integer, String > ();

        // By using put() method is to add
        // key-value pairs in a HashMap
        map.put(10, "C");
        map.put(20, "C++");
        map.put(50, "JAVA");
        map.put(40, "PHP");
        map.put(30, "SFDC");

        // Display HashMap
        System.out.println("HashMap: " + map);

        // By using size() method is to return
        // the size of this HashMap
        int size = map.size();

        // Display size
        System.out.print("map.size(): " + size);
    }
}

Output

HashMap: {50=JAVA, 20=C++, 40=PHP, 10=C, 30=SFDC}
map.size(): 5