Check for the existence of a key in Java IdentityHashMap

Use the containsKey() method to check whether a particular key exists in IdentityHashMap or not.

Create a IdentityHashMap

Map<String, Integer> m = newIdentityHashMap<String, Integer>();
m.put("1", 100);
m.put("2", 200);
m.put("3", 300);
m.put("4", 150);
m.put("5", 110);
m.put("6", 50);
m.put("7", 90);
m.put("8", 250);
m.put("9", 350);
m.put("10", 450);

Now, let’s say we need to check whether key 7 exists or not. For that, use the containsKey() method like this

m.containsKey(“7”)

The following is an example to check for the existence of a key in IdentityHashMap

Example

 Live Demo

import java.util.*;
public class Demo {
   public static void main(String[] args) {
      Map<String, Integer> m = newIdentityHashMap<String, Integer>();
      m.put("1", 100);
      m.put("2", 200);
      m.put("3", 300);
      m.put("4", 150);
      m.put("5", 110);
      m.put("6", 50);
      m.put("7", 90);
      m.put("8", 250);
      m.put("9", 350);
      m.put("10", 450);
      System.out.println("IdentityHashMap elements\n"+ m);
      System.out.println("Size = " + m.size());
      System.out.println("Is key 7 in the Map? " + m.containsKey("7"));
   }
}

Output

The output is as follows

IdentityHashMap elements
{2=200, 4=150, 9=350, 7=90, 10=450, 6=50, 5=110, 8=250, 1=100, 3=300}
Size = 10
Is key 7 in the Map? True