Set isEmpty() method in Java with Examples

The java.util.Set.isEmpty() method is used to check if a Set is empty or not. It returns True if the Set is empty otherwise it returns False.

Syntax:

boolean isEmpty()

Parameters: This method does not take any parameter

Return Value: The method returns True if the set is empty else returns False.

Below program illustrate the java.util.Set.isEmpty() method:

// Java code to illustrate isEmpty()
import java.io.*;
import java.util.*;

public class SetDemo {
    public static void main(String args[])
    {
        // Creating an empty Set
        Set<String> set = new HashSet<String>();

        // Use add() method to add elements into the Set
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("4");
        set.add("Geeks");

        // Displaying the Set
        System.out.println("Set: " + set);

        // Check for the empty set
        System.out.println("Is the set empty? " + set.isEmpty());

        // Clearing the set using clear() method
        set.clear();

        // Again Checking for the empty set
        System.out.println("Is the set empty? " + set.isEmpty());
    }
}

Output:

Set: [4, Geeks, Welcome, To]
Is the set empty? false
Is the set empty? true

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Set.html#isEmpty()