Home » Java programming language

Java IdentityHashMap keySet() Method with Example

IdentityHashMap Class keySet() method: Here, we are going to learn about the keySet() method of IdentityHashMap Class with its syntax and example.
Submitted by Preeti Jain, on March 06, 2020

IdentityHashMap Class keySet() method

• keySet() method is available in java.util package.
• keySet() method is used to get a set of all the existing keys in this IdenityHashMap to be viewed in a Set.
• keySet() 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.
• keySet() method does not throw an exception at the time of returning the key set.

Syntax:

    public Set keySet();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Set, it returns Set view of all the existing keys in this IdenityHashMap.

Example:

// Java program to demonstrate the example 
// of Set keySet() method of IdentityHashMap 

import java.util.*;

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

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

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

        // By using keySet() method is to
        // return the set of of keys exists
        // in this IdentityHashMap to be viewed in 
        // a Set

        Set s = map.keySet();

        // Display status
        System.out.print("map.keySet(): ");
        System.out.println(s);
    }
}

Output

IdentityHashMap: {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C}
map.keySet(): [20, 40, 50, 30, 10]