Queue remove() method in Java - GeeksforGeeks

26 Sep, 2018
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.
// 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());    }}
Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 2: With the help of ArrayDeque.
// 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());    }}
Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 3: With the help of LinkedBlockingDeque.
// 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());    }}
Queue: [7855642, 35658786, 5278367, 74381793]
Queue's head: 7855642
Queue's head: 35658786

Program 4: With the help of ConcurrentLinkedDeque.
// 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());    }}
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.
// 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);        }    }}
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–
Java - util package
java-basics
Java-Collections
Java-Functions
java-queue
Java
Java
Java-Collections
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Stream In Java
Constructors in Java
Different ways of Reading a text file in Java
Exceptions in Java
Functional Interfaces in Java
Generics in Java
Comparator Interface in Java with Examples
Introduction to Java
HashMap get() Method in Java
Strings in Java