Collection isEmpty() method in Java with Examples
Last Updated :
24 Jul, 2024
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The isEmpty() of java.util.Collection interface is used to check if the Collection upon which it is called is empty or not. This method does return a boolean value indicating whether the collection is empty or not. Here's the correct information for the isEmpty() method:
Syntax:
boolean isEmpty()Parameters:
This method does not accept any parameter.
Return Value:
This method returns a boolean value, which indicates whether the collection is empty or not. The below examples illustrate the Collection isEmpty() method:
Example 1: Using LinkedList Class
// Java code to illustrate boolean isEmpty() method
import java.io.*;
import java.util.*;
public class GFG {
public static void main(String[] args) {
// Creating an empty LinkedList
Collection<String> list = new LinkedList<String>();
// Use add() method to add elements to the list
list.add("Geeks");
list.add("for");
list.add("Geeks");
// Output the present list
System.out.println("The list is: " + list);
// Check if list is empty using isEmpty() method
System.out.println("Is the LinkedList empty: " + list.isEmpty());
// Clearing the LinkedList
list.clear();
// Printing the new list
System.out.println("The new List is: " + list);
// Check if list is empty using isEmpty() method
System.out.println("Is the LinkedList empty: " + list.isEmpty());
}
}
Output
The list is: [Geeks, for, Geeks] Is the LinkedList empty: false The new List is: [] Is the LinkedList empty: true
Example 2: Using ArrayDeque Class
// Java code to illustrate isEmpty() method
import java.util.*;
public class ArrayDequeDemo {
public static void main(String[] args) {
// Creating an empty ArrayDeque
Collection<String> de_que = new ArrayDeque<String>();
// Use add() method to add elements to the Deque
de_que.add("Welcome");
de_que.add("To");
de_que.add("Geeks");
de_que.add("4");
de_que.add("Geeks");
// Displaying the ArrayDeque
System.out.println("ArrayDeque: " + de_que);
// Check if ArrayDeque is empty using isEmpty() method
System.out.println("Is the ArrayDeque empty: " + de_que.isEmpty());
// Clearing the ArrayDeque
de_que.clear();
// Printing the new ArrayDeque
System.out.println("The new ArrayDeque is: " + de_que);
// Check if ArrayDeque is empty using isEmpty() method
System.out.println("Is the ArrayDeque empty: " + de_que.isEmpty());
}
}
Output
ArrayDeque: [Welcome, To, Geeks, 4, Geeks] Is the ArrayDeque empty: false The new ArrayDeque is: [] Is the ArrayDeque empty: true
Example 3: Using ArrayList Class
// Java code to illustrate isEmpty() method
import java.io.*;
import java.util.*;
public class ArrayListDemo {
public static void main(String[] args) {
// Create an empty ArrayList with an initial capacity
Collection<Integer> arrlist = new ArrayList<Integer>(5);
// Use add() method to add elements to the list
arrlist.add(15);
arrlist.add(20);
arrlist.add(25);
// Print all the elements available in the list
System.out.println("ArrayList: " + arrlist);
// Check if list is empty using isEmpty() method
System.out.println("Is the ArrayList empty: " + arrlist.isEmpty());
// Clearing the ArrayList
arrlist.clear();
// Printing the new ArrayList
System.out.println("The new ArrayList is: " + arrlist);
// Check if ArrayList is empty using isEmpty() method
System.out.println("Is the ArrayList empty: " + arrlist.isEmpty());
}
}
Output
ArrayList: [15, 20, 25] Is the ArrayList empty: false The new ArrayList is: [] Is the ArrayList empty: true
Reference:
https://docs.oracle.com/javase/9/docs/api/java/util/Collection.html#isEmpty--
