Set equals() Method in Java (original) (raw)

Last Updated : 04 Feb, 2025

In Java, the equals() method of the Set class is used to compare two sets for equality. It checks if two sets contain the same elements regardless of their order.

**Example 1: This example demonstrates how to **compare two **HashSet collections for equality of type string using the equals() method.

Java `

// Java program to demonstrate // the working of equals() method import java.util.*;

public class Geeks { public static void main(String[] argv) { // Creating object of Set Set s1 = new HashSet();

    s1.add("A");
    s1.add("B");
    s1.add("C");
    s1.add("D");
    s1.add("E");

    System.out.println("First Set: " + s1);

    // Creating another object of Set
    Set<String> s2 = new HashSet<String>();

    s2.add("A");
    s2.add("B");
    s2.add("C");
    s2.add("D");
    s2.add("E");

    System.out.println("Second Set: " + s2);

    // comparing first Set to another
    // using equals() method
    boolean value = s1.equals(s2);

    System.out.println("Are both set equal? " + value);
}

}

`

Output

First Set: [A, B, C, D, E] Second Set: [A, B, C, D, E] Are both set equal? true

Syntax of equals() Method

boolean equals(Object o)

• **Parameter: This method takes an object as a parameter.
• **Return Type: This method returns "true" if the two sets are equal, otherwise it returns "false".

**Example 2: This example demonstrates how to **compare two HashSet collections for equality of type integer using the equals() method.

Java `

// Java Program to demonstrates // the working of equals() method import java.util.*;

public class Geeks { public static void main(String[] argv) { // Creating object of Set Set s1 = new HashSet();

    s1.add(10);
    s1.add(20);
    s1.add(30);
    s1.add(40);
    s1.add(50);

    System.out.println("First Set: " + s1);

    // Creating another object of Set
    Set<Integer> s2 = new HashSet<Integer>();

    s2.add(10);
    s2.add(20);
    s2.add(30);

    System.out.println("Second Set: " + s2);

    // comparing first Set to another
    // using equals() method
    boolean value = s1.equals(s2);

    System.out.println("Are both set equal? " + value);
}

}

`

Output

First Set: [50, 20, 40, 10, 30] Second Set: [20, 10, 30] Are both set equal? false