Queue remove() method in Java

The remove() method of Queue Interface returns and removes the element at the front the container. It deletes the head of the container. The method throws an NoSuchElementException when the Queue is empty.

Syntax:

E remove()

Returns: This method returns the head of the Queue.

Exception: The function throws an NoSuchElementException when the Queue is empty.

Below programs illustrate remove() method of Queue:



Program 1: With the help of LinkedList.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate remove()
// method of Queue
  
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of Queue
        Queue<Integer> Q
            = new LinkedList<Integer>();
  
        // Add numbers to end of Queue
        Q.add(7855642);
        Q.add(35658786);
        Q.add(5278367);
        Q.add(74381793);
  
        // print queue
        System.out.println("Queue: " + Q);
  
        // print head and deletes the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print head and deleted the head
        System.out.println("Queue's head: " + Q.remove());
    }
}

chevron_right


Output:

Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 2: With the help of ArrayDeque.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate remove()
// method of Queue
  
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of Queue
        Queue<Integer> Q
            = new ArrayDeque<Integer>();
  
        // Add numbers to end of Queue
        Q.add(7855642);
        Q.add(35658786);
        Q.add(5278367);
        Q.add(74381793);
  
        // print queue
        System.out.println("Queue: " + Q);
  
        // print head and deletes the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print head and deleted the head
        System.out.println("Queue's head: " + Q.remove());
    }
}

chevron_right


Output:

Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 3: With the help of LinkedBlockingDeque.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate remove()
// method of Queue
  
import java.util.*;
import java.util.concurrent.LinkedBlockingDeque;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of Queue
        Queue<Integer> Q
            = new LinkedBlockingDeque<Integer>();
  
        // Add numbers to end of Queue
        Q.add(7855642);
        Q.add(35658786);
        Q.add(5278367);
        Q.add(74381793);
  
        // print queue
        System.out.println("Queue: " + Q);
  
        // print head and deletes the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print head and deleted the head
        System.out.println("Queue's head: " + Q.remove());
    }
}

chevron_right


Output:

Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 4: With the help of ConcurrentLinkedDeque.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate remove()
// method of Queue
  
import java.util.*;
import java.util.concurrent.ConcurrentLinkedDeque;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of Queue
        Queue<Integer> Q
            = new ConcurrentLinkedDeque<Integer>();
  
        // Add numbers to end of Queue
        Q.add(7855642);
        Q.add(35658786);
        Q.add(5278367);
        Q.add(74381793);
  
        // print queue
        System.out.println("Queue: " + Q);
  
        // print head and deletes the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print head and deleted the head
        System.out.println("Queue's head: " + Q.remove());
    }
}

chevron_right


Output:

Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Below programs illustrate exceptions thrown by this method:

Program 5: To show NoSuchElementException.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate remove()
// method of Queue
  
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of Queue
        Queue<Integer> Q
            = new LinkedList<Integer>();
  
        // Add numbers to end of Queue
        Q.add(423);
        Q.add(3432);
  
        // print queue
        System.out.println("Queue: " + Q);
  
        // print head and deletes the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print head and deleted the head
        System.out.println("Queue's head: " + Q.remove());
  
        // print queue
        System.out.println("Queue: " + Q);
  
        try {
            // Queue is empty now hence exception
            System.out.println("Queue's head: " + Q.element());
        }
        catch (Exception e) {
            System.out.println("Exception: " + e);
        }
    }
}

chevron_right


Output:

Queue: [423, 3432]
Queue's head: 423
Queue's head: 3432
Queue: []
Exception: java.util.NoSuchElementException

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/Queue.html#remove–



My Personal Notes arrow_drop_up

The function of education is to teach one to think intensively and to think critically

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.