Java IdentityHashMap equals() method

The equal() method of the Java IdentityHashMap is used to check the equality of specified Object with the calling IdentityHashMap.

Syntax

Parameters

o - Object whose equality is to be compared with the calling IdentityHashMap.

Return

True, if the specified object is equal to the calling IdentityHashMap.

Example 1

import java.util.IdentityHashMap;

public class IdentityHashMapEqualsExample1 {
    public static void main(String[] args) {
   //Creating an object of IdentityHashMap class
   IdentityHashMap<String,Integer> map1 = new IdentityHashMap<String,Integer>(4);
   
   //Putting key-value pairs inside map1
   map1.put("Java", 1);
   map1.put("is", 2);
   map1.put("programming", 3);
   map1.put("language", 4);
   
   //Creating another object of the Java IdentityHashMap
   IdentityHashMap<String,Integer> map2 = new IdentityHashMap<String,Integer>(4);
   
   //Putting key-value pairs inside map2
   map2.put("Java", 1);
   map2.put("is", 2);
   map2.put("programming", 3);
   map2.put("language", 4);
   
   //Creating another object of the Java IdentityHashMap
   IdentityHashMap<String,Integer> map3 = new IdentityHashMap<String,Integer>(4);
   
   //Putting key-value pairs inside map3
   map3.put("Java", 0);
   map3.put("is", 1);
   map3.put("programming", 2);
   map3.put("language", 3);
   
   //Checking if map1 and map2 are equal
   System.out.println(map1.equals(map2));
   
   //Checking if map1 and map3 are equal
   System.out.println(map1.equals(map3));
   
   //Checking if map2 and map3 are equal
   System.out.println(map2.equals(map3));
}
}

Output:

true
false
false

Example 2

import java.util.IdentityHashMap;

class Student{
    private int roll;
    private String name;
    private int standard;
    
    public Student(int roll,String name,int standard){
        this.roll = roll;
        this.name = name;
        this.standard = standard;
    }
    
    public String disp(){
        return roll+" "+name+" "+standard;
    }
}

public class IdentityHashMapEqualsExample2 {
    public static void main(String[] args) {
        
        //Creating Objects of Student class
        Student stud1 = new Student(1 ,"Ram ",10);
        Student stud2 = new Student(2 ,"Shyam ",10);
        Student stud3 = new Student(3 ,"Aman ",12);
        Student stud4 = new Student(4 ,"Harsh ",12);
        Student stud5 = new Student(5 ,"Shivam",11);
        
        //Creating an instance of IdentityHashMap
        IdentityHashMap<Integer,Student> map1 = new IdentityHashMap<Integer,Student>(5);
        IdentityHashMap<Integer,Student> map2 = new IdentityHashMap<Integer,Student>(5);
        IdentityHashMap<Integer,Student> map3 = new IdentityHashMap<Integer,Student>(5);
        
        //Inserting the Student class objects into map1
        map1.put(1,stud1);
        map1.put(2,stud2);
        map1.put(3,stud3);
        map1.put(4,stud4);
        
        //Inserting the Student class objects into map2
        map2.put(1,stud1);
        map2.put(2,stud2);
        map2.put(3,stud3);
        map2.put(4,stud4);
        
        //Inserting the Student class objects into map1
        map3.put(1,stud1);
        map3.put(2,stud2);
        map3.put(3,stud3);
        map3.put(4,stud5);
        
        //Checking if map1 and map2 are equal
        System.out.println(map1.equals(map2));
   
        //Checking if map1 and map3 are equal
        System.out.println(map1.equals(map3));
   
        //Checking if map2 and map3 are equal
        System.out.println(map2.equals(map3));
}
}

Output: