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
