SatyaCodes

Java- IdentityHashMap

IdentityHashMap

  • It is exactly same as HashMap (including methods&constructors) except following diffrences

  • In the case of Normal HashMap JVM will use .equals() method to identify Duplicate keys, which is ment for Content comparision

  • But, In the case of IdentityHashMap JVM will use == operator to identify Duplicate keys, which is ment for reference comparision or address comparision

== is for reference comparision or address comparision

.equals () is for content comparision

HashMap Example

public class HashMapDemo {
 public static void main(String[] a) {
  HashMap m = new HashMap();
  m.put(new Integer(10), "Satya");
  m.put(new Integer(10), "Surya");
  System.out.println(m);
// {10=Surya}
}
}
---------------
{10=Surya}


IdentityHashMap Example

public class IdentityHashMapDemo {
public static void main(String[] args) 
{
IdentityHashMap  m = new IdentityHashMap();
  m.put(new Integer(10), "Satya");
  m.put(new Integer(10), "Surya");
  System.out.println(m);
// {10=Satya, 10=Surya}
	}
}
-----------
{10=Satya, 10=Surya}
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