ConcurrentLinkedQueue offer() method in Java

The offer() method of ConcurrentLinkedQueue is used to insert the element, passed as parameter, at the tail of this ConcurrentLinkedQueue. This method returns True if insertion is successful. ConcurrentLinkedQueue is unbounded, so this method offer() will never returns false.

Syntax:

public boolean offer(E e)

Parameter: This method takes a single parameter e which represents the element we want to insert into this ConcurrentLinkedQueue.

Returns: This method returns true after successful insertion of element.

Exception: This method throws NullPointerException if the specified element is null.



Below programs illustrate offer() method of ConcurrentLinkedQueue:

Example 1: To demonstrate offer() method of ConcurrentLinkedQueue to add String.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate offer()
// method of ConcurrentLinkedQueue
  
import java.util.concurrent.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create an ConcurrentLinkedQueue
        ConcurrentLinkedQueue<String>
            queue = new ConcurrentLinkedQueue<String>();
  
        // Add String to queue using offer() method
        queue.offer("Aman");
        queue.offer("Amar");
        queue.offer("Sanjeet");
        queue.offer("Rabi");
  
        // Displaying the existing ConcurrentLinkedQueue
        System.out.println("ConcurrentLinkedQueue: " + queue);
    }
}

chevron_right


Output:

ConcurrentLinkedQueue: [Aman, Amar, Sanjeet, Rabi]

Example 2: To demonstrate offer() method of ConcurrentLinkedQueue for adding Numbers.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate offer()
// method of ConcurrentLinkedQueue
  
import java.util.concurrent.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create an ConcurrentLinkedQueue
        ConcurrentLinkedQueue<Integer>
            queue = new ConcurrentLinkedQueue<Integer>();
  
        // Add Numbers to queue using offer
        queue.offer(4353);
        queue.offer(7824);
        queue.offer(78249);
        queue.offer(8724);
  
        // Displaying the existing ConcurrentLinkedQueue
        System.out.println("ConcurrentLinkedQueue: " + queue);
    }
}

chevron_right


Output:

ConcurrentLinkedQueue: [4353, 7824, 78249, 8724]

Example 3: To demonstrate NullPointerException thrown by offer() method for adding Null.

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java Program Demonstrate offer()
// method of ConcurrentLinkedQueue
  
import java.util.concurrent.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create an ConcurrentLinkedQueue
        ConcurrentLinkedQueue<Integer>
            queue = new ConcurrentLinkedQueue<Integer>();
  
        // Add null to queue
        try {
            queue.offer(null);
        }
        catch (NullPointerException e) {
            System.out.println("Exception thrown"
                               + " while adding null: " + e);
        }
    }
}

chevron_right


Output:

Exception thrown while adding null: java.lang.NullPointerException

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedQueue.html#offer-E-



My Personal Notes arrow_drop_up

I am a Developer I love to code and bring my ideas alive

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.