AbstractMap.SimpleEntry equals(Object o) Method in Java with Examples

AbstractMap.SimpleEntry<K, V> is used to maintain a key and a value entry. The value can be changed using the equals? method. This class facilitates the process of building custom map implementations.

equals(Object o) method of AbstractMap.SimpleEntry<K, V> used to compare the specified object passed as parameter with this entry for equality.The method returns true if the given object also contains a map entry and the two entries represent the same mapping.

Two entries e1 and e2 represent the same mapping if

 (e1.getKey()==null ?
    e2.getKey()==null :
    e1.getKey().equals(e2.getKey()))
   &&
   (e1.getValue()==null ?
    e2.getValue()==null :
    e1.getValue().equals(e2.getValue()))

Syntax:

public V equals(Object o)

Parameters: This method accepts object to be compared for equality with this map entry.

Return value: This method true if the specified object is equal to this map entry.

Below programs illustrate equals(Object o) method:
Program 1:

// Java program to demonstrate
// AbstractMap.SimpleEntry.equals() method

import java.util.*;

public class GFG {

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static void main(String[] args)
    {

        // create two maps
        AbstractMap.SimpleEntry<Integer, Integer> map1
            = new AbstractMap.SimpleEntry(0, 123);

        AbstractMap.SimpleEntry<Integer, Integer> map2
            = new AbstractMap.SimpleEntry(0, 123);

        // compare both maps
        boolean answer = map1.equals(map2);

        // print result
        System.out.println("Map 1 is equal to Map2 -> "
                           + answer);
    }
}

Output:

Map 1 is equal to Map2 -> true

Program 2:

// Java program to demonstrate
// AbstractMap.SimpleEntry.equals() method

import java.util.*;

public class GFG {

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static void main(String[] args)
    {

        // create two maps
        AbstractMap.SimpleEntry<String, String> map1
            = new AbstractMap
                  .SimpleEntry<String, String>("Captain:", "Dhoni");
        AbstractMap.SimpleEntry<String, String> map2
            = new AbstractMap
                  .SimpleEntry<String, String>("Captain:", "Kohli");

        // compare both maps
        boolean answer = map1.equals(map2);

        // print result
        System.out.println("Map 1 is equal to Map2 -> "
                           + answer);
    }
}

Output:

Map 1 is equal to Map2 -> false

References: https://docs.oracle.com/javase/10/docs/api/java/util/AbstractMap.SimpleEntry.html##equals(java.lang.Object)