SortedMap equals() method in Java with Examples

In Java, SortedMap is an interface that extends the Map interface and maintains its key-value pairs in ascending order based on the keys’ natural ordering or a custom comparator. The equals(Object obj) method of the SortedMap interface is used to compare the SortedMap to the specified object for equality.

The equals(Object obj) method returns true if the specified object is also a SortedMap and has the same mappings as the SortedMap being compared, and false otherwise. Here’s an example of how to use the equals() method:

Java

import java.util.SortedMap;
import java.util.TreeMap;

public class SortedMapExample {
  public static void main(String[] args) {
    // Create two SortedMaps and add some key-value pairs
    SortedMap<String, Integer> sortedMap1 = new TreeMap<>();
    sortedMap1.put("John", 30);
    sortedMap1.put("Alice", 25);
    sortedMap1.put("Bob", 40);

    SortedMap<String, Integer> sortedMap2 = new TreeMap<>();
    sortedMap2.put("Alice", 25);
    sortedMap2.put("Bob", 40);
    sortedMap2.put("John", 30);

    // Compare the two SortedMaps for equality
    boolean areEqual = sortedMap1.equals(sortedMap2);

    System.out.println("Are the two SortedMaps equal? " + areEqual);
  }
}

Output

Are the two SortedMaps equal? true

The equals() method in SortedMap Java is used to check for equality between two SortedMap instances. It verifies whether the elements of one SortedMap passed as a parameter is equal to the elements of this SortedMap or not. Syntax:

boolean equals(object obj)

Parameters: The method accepts one parameter obj of this map type and refers to the map whose equality is to be checked with this map. Return Value: The method returns true if the equality holds for both the object map else it returns false. Note: The equals() method in SortedMap is inherited from the Map interface in Java. Below programs illustrate the equals() method: 

Program 1:

Java

// Java code to illustrate
// the equals() method

import java.util.*;

public class Map_Demo {
    public static void main(String[] args)
    {

        // Creating an empty SortedMap
        SortedMap<Integer, String> map1
            = new TreeMap<Integer, String>();
        SortedMap<Integer, String> map2
            = new TreeMap<Integer, String>();

        // Mapping string values to int keys
        map1.put(10, "Geeks");
        map1.put(15, "4");
        map1.put(20, "Geeks");
        map1.put(25, "Welcomes");
        map1.put(30, "You");

        // Mapping string values to int keys
        map2.put(10, "Geeks");
        map2.put(15, "4");
        map2.put(20, "Geeks");
        map2.put(25, "Welcomes");
        map2.put(30, "You");

        // Displaying the Map1
        System.out.println("First Map: "
                           + map1);

        // Displaying the Map2
        System.out.println("Second Map: "
                           + map2);

        // Checking the equality
        System.out.println(
            "Equality: "
            + map1.equals(map2));
    }
}

Program 2:

Java

// Java code to illustrate
// the equals() method

import java.util.*;

public class Map_Demo {
    public static void main(String[] args)
    {

        // Creating an empty SortedMap
        SortedMap<Integer, String> map1
            = new TreeMap<Integer, String>();
        SortedMap<Integer, String> map2
            = new TreeMap<Integer, String>();

        // Mapping string values
        // to int keys for map1
        map1.put(10, "Geeks");
        map1.put(15, "4");
        map1.put(20, "Geeks");
        map1.put(25, "Welcomes");
        map1.put(30, "You");

        // Mapping string values
        // to int keys for map2
        map2.put(10, "Geeks");
        map2.put(15, "4");
        map2.put(20, "Geek");
        map2.put(25, "Welcomes");
        map2.put(30, "You");

        // Displaying the map 1
        System.out.println("First Map: "
                           + map1);

        // Displaying the map 2
        System.out.println("Second Map: "
                           + map2);

        // Displaying the equality
        System.out.println("Equality: "
                           + map1.equals(map2));
    }
}

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#equals(java.lang.Object)