HashSet equals() method in Java with Example - GeeksforGeeks

19 Feb, 2020
The equals() method of java.util.HashSet class is used verify the equality of an Object with a HashSet and compare them. The list returns true only if both HashSet contains same elements, irrespective of order.
Syntax:
public boolean equals(Object o)
Parameters: This method takes the object o as a parameter to be compared for equality with this set.
Returns Value: This method returns true if the specified object is equal to this set.
Below are the examples to illustrate the equals() method.
Example 1:
// Java program to demonstrate equals()// method of HashSet  import java.util.*;  public class GFG {    public static void main(String[] argv)    {          // Creating object of HashSet<String>        HashSet<String>            arrset1 = new HashSet<String>();          // Populating arrset1        arrset1.add("A");        arrset1.add("B");        arrset1.add("C");        arrset1.add("D");        arrset1.add("E");          // print arrset1        System.out.println("First HashSet: "                           + arrset1);          // Creating another object of HashSet<String>        HashSet<String>            arrset2 = new HashSet<String>();          // Populating arrset2        arrset2.add("A");        arrset2.add("B");        arrset2.add("C");        arrset2.add("D");        arrset2.add("E");          // print arrset2        System.out.println("Second HashSet: "                           + arrset2);          // comparing first HashSet to another        // using equals() method        boolean value            = arrset1.equals(arrset2);          // print the value        System.out.println("Are both set equal: "                           + value);    }}
First HashSet: [A, B, C, D, E]
Second HashSet: [A, B, C, D, E]
Are both set equal: true

Example 2:
// Java program to demonstrate equals()// method of HashSet  import java.util.*;  public class GFG1 {    public static void main(String[] argv)    {          // Creating object of HashSet        HashSet<Integer>            arrset1 = new HashSet<Integer>();          // Populating arrset1        arrset1.add(10);        arrset1.add(20);        arrset1.add(30);        arrset1.add(40);        arrset1.add(50);          // print arrset1        System.out.println("First HashSet: "                           + arrset1);          // Creating another object of HashSet        HashSet<Integer>            arrset2 = new HashSet<Integer>();          // Populating arrset2        arrset2.add(10);        arrset2.add(20);        arrset2.add(30);          // print arrset2        System.out.println("Second HashSet: "                           + arrset2);          // comparing first HashSet to another        // using equals() method        boolean value = arrset1.equals(arrset2);          // print the value        System.out.println("Are both set equal: "                           + value);    }}
First HashSet: [50, 20, 40, 10, 30]
Second HashSet: [20, 10, 30]
Are both set equal: false

vivekpant
Java - util package
Java-Collections
Java-Functions
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