AbstractCollection isEmpty() Method in Java with Examples

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