The isEmpty() method of Java AbstractCollection is used to check and verify if a Collection is empty or not. It returns True if the Collection is empty else it returns False.
Syntax:
AbstractCollection.isEmpty()
Parameters: The method does not take any parameter.
Return Value: The function returns True if the collection is empty else it returns False.
Below program illustrate the use of AbstractCollection.isEmpty() method:
Program 1:
// Java code to illustrate isEmpty() method import java.util.*;import java.util.AbstractCollection; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty Collection AbstractCollection<String> abs = new TreeSet<String>(); // Use add() method to add // elements into the Collection abs.add("Welcome"); abs.add("To"); abs.add("Geeks"); abs.add("4"); abs.add("Geeks"); abs.add("TreeSet"); // Displaying the Collection System.out.println("Collection: " + abs); // Check for the empty collection System.out.println("Is the collection empty? " + abs.isEmpty()); // Clearing the collection // using clear() method abs.clear(); // Again Checking for the empty collection System.out.println("Is the collection empty? " + abs.isEmpty()); }} |
Output:
Collection: [4, Geeks, To, TreeSet, Welcome] Is the collection empty? false Is the collection empty? true
Program 2:
// Java code to illustrate isEmpty() method import java.util.*;import java.util.AbstractCollection; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty Collection AbstractCollection<String> abs = new ArrayList<String>(); // Use add() method to add // elements into the Collection abs.add("Welcome"); abs.add("To"); abs.add("Geeks"); abs.add("4"); abs.add("Geeks"); abs.add("ArrayList"); // Displaying the Collection System.out.println("Collection: " + abs); // Check for the empty collection System.out.println("Is the collection empty? " + abs.isEmpty()); // Clearing the collection using clear() method abs.clear(); // Again Checking for the empty collection System.out.println("Is the collection empty? " + abs.isEmpty()); }} |
Output:
Collection: [Welcome, To, Geeks, 4, Geeks, ArrayList] Is the collection empty? false Is the collection empty? true
