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()