Java ConcurrentLinkedQueue add() method

The add() method of ConcurrentLinkedQueue class inserts the specified element at the tail of this ConcurrentLinkedQueue. The addAll() method overrides the addAll in class AbstractQueue<E>

Syntax

Parameter

e- It is the element to add

Specified By

The add() method of ConcurrentLinkedQueue class is specified by :

add() method in interface Queue<E>.
add() method in interface Collection<E>.

Return Value

The add() method returns a Boolean value true.

Throws

NullPointerException: If the specified element e is null.

Example 1

import java.util.concurrent.ConcurrentLinkedQueue;
public class ConcurrentLinkedQueueAddExample1 {
public static void main(String[] args) {
int j =1;
ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
for (int i = 1; i <=5; i++) {
//  Adding items to the tail of this queue
queue.add(i);
System.out.println("After adding "+ j++ +" to the queue :");
System.out.println(queue);
        }
    }
}

Test it Now

Output:

After adding 1 to the queue :
[1]
After adding 2 to the queue :
[1, 2]
After adding 3 to the queue :
[1, 2, 3]
After adding 4 to the queue :
[1, 2, 3, 4]
After adding 5 to the queue :
[1, 2, 3, 4, 5]

Example 2

import java.util.Collections;
import java.util.concurrent.ConcurrentLinkedQueue;
public class ConcurrentLinkedQueueAddExample2 {
public static void main(String[] args) {
        Integer[] val = {0, 1};
ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
queue.add(718);
queue.add(8);
queue.add(18);
queue.add(119);
System.out.println("Queue : ");
for (Integer n : queue) {
System.out.println(n);
val[0] = Collections.max(queue);
val[1] = Collections.min(queue);
        }
System.out.println("Max number = "+ val[0]);
System.out.println("Min number = "+ val[1]);
    }
}

Test it Now

Output:

Queue :
718
8
18
119
Max number = 718
Min number = 8

Example 3

import java.util.concurrent.ConcurrentLinkedQueue;
class Name{
private String name;

public Name(String name) {
this.name = name;
    }
public String toString(){
return "Name = "+ this.name;
    }
}
public class ConcurrentLinkedQueueAddExample3 {
public static int i=1;
public static void main(String[] args) {
ConcurrentLinkedQueue<Name> queue = new ConcurrentLinkedQueue<Name>();
        Name s1 = new Name("Reema");
        Name s2 = new Name("Jyoti");
        Name s3 = new Name("Rahul");
        Name s4 = new Name("Anushtha");
queue.add(s1);
queue.add(s2);
queue.add(s3);
queue.add(s4);
for (Name xyz : queue){
System.out.println(i++ + ". "+xyz);
        }
    }
}

Test it Now

Output:

1. Name = Reema
2. Name = Jyoti
3. Name = Rahul
4. Name = Anushtha

Example 4

import java.util.concurrent.ConcurrentLinkedQueue;
public class ConcurrentLinkedQueueAddExample4 {
public static void main(String[] args) {
ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
queue.add(null);
queue.add(90);
queue.add(187);
    }
}

Test it Now

Output:

Exception in thread "main" java.lang.NullPointerException
	at java.util.concurrent.ConcurrentLinkedQueue.checkNotNull(ConcurrentLinkedQueue.java:920)
	at java.util.concurrent.ConcurrentLinkedQueue.offer(ConcurrentLinkedQueue.java:327)
	at java.util.concurrent.ConcurrentLinkedQueue.add(ConcurrentLinkedQueue.java:297)
	at com.javaTpoint.ConcurrentLinkedQueueAddExample4.main(ConcurrentLinkedQueueAddExample4.java:7)

If any of the specified elements in this queue is null, it will give NullPointerException as described above.

Next TopicJava ConcurrentLinkedQueue

← prev next →