IdentityHashMap @ Java

IdentityHashMap is a HashTable -based implementation of the Map Interface. Normal HashMap compares keys using the .equals method but Identity HashMap compares its keys using the == operator. Hence, ‘Java’ and new String(‘Java’) are considered as two different keys. The initial size of Identity HashMap is 21, while the initial size of a normal HashMap is 16.

Code Snippet:-

import java.util.IdentityHashMap;
public class MyClass {
	public static void main(final String[] args) {
		final IdentityHashMap identityHashMap = new IdentityHashMap();
		identityHashMap.put("Java", "Java-7");
		identityHashMap.put(new String("Java"), "Java-8");

		for (final String str : identityHashMap.keySet()) {
			System.out.println("Key : " + str + " and Value : " + identityHashMap.get(str));
		}

		System.out.println("Size of map is : " + identityHashMap.size());
	}
}

Output:-

Key : Java and Value : Java-7
Key : Java and Value : Java-8
Size of map is : 2