LinkedBlockingQueue put() method in Java with Examples

The put(E e) method of LinkedBlockingQueue inserts element passed as parameter to method at the tail of this LinkedBlockingQueue, if queue is not full. If the queue is full, then this method will wait for space to become available and after space is available, it inserts the element to LinkedBlockingQueue.

Syntax:

public void put(E e) throws InterruptedException

Parameter: This method takes a mandatory parameter e which is the element to be inserted in LinkedBlockingQueue.
Return Value: The method does not return anything.

Exception: This method throws following exceptions:  

• InterruptedException– when the interruption occurred at time of waiting for queue to become available
• NullPointerException– if the element passed to method is null

Below programs illustrates put(E e) method of LinkedBlockingQueue class:

Program 1: Prints Element of LinkedBlockingQueue after adding new names to queue using put() method. 

Java

// Java Program Demonstrate put(E e)
// method of LinkedBlockingQueue

import java.util.concurrent.LinkedBlockingQueue;

public class GFG {

    public static void main(String[] args)
        throws InterruptedException
    {
        // define capacity of LinkedBlockingQueue
        int capacityOfQueue = 4;

        // create object of LinkedBlockingQueue
        LinkedBlockingQueue<String> linkedQueue
            = new LinkedBlockingQueue<String>(capacityOfQueue);

        // Add element using put() method
        linkedQueue.put("Karan");
        linkedQueue.put("Suraj");
        linkedQueue.put("Harsh");
        linkedQueue.put("Rahul");

        // print elements of queue
        System.out.println("Items in Queue are " + linkedQueue);
    }
}

Output:

Items in Queue are [Karan, Suraj, Harsh, Rahul]

Program 2: Add Employee object using put method in LinkedBlockingQueue

Java

// Java Program Demonstrate put()
// method of LinkedBlockingQueue

import java.util.Iterator;
import java.util.concurrent.LinkedBlockingQueue;
public class GFG {

    public void PutDemo() throws InterruptedException
    {
        // define capacity of LinkedBlockingQueue
        int capacityOfQueue = 5;

        // create object of LinkedBlockingQueue
        LinkedBlockingQueue<Employee> linkedQueue
            = new LinkedBlockingQueue<Employee>(capacityOfQueue);

        // Add element to LinkedBlockingQueue
        Employee emp1 = new Employee("Ranjeet", "Tester", "29000", 27);
        Employee emp2 = new Employee("Sanjeet", "Manager", "98000", 34);
        Employee emp3 = new Employee("Karan", "Analyst", "44000", 30);

        // Add Employee Objects to linkedQueue
        // Using put(E e)
        linkedQueue.put(emp1);
        linkedQueue.put(emp2);
        linkedQueue.put(emp3);

        System.out.println("Details of Employees:");
        // print details of linkedQueue
        Iterator itr = linkedQueue.iterator();
        while (itr.hasNext())
            System.out.println(itr.next());
    }

    // create an Employee Object with name,
    // position, salary and age as attributes
    public class Employee {

        public String name;
        public String position;
        public String salary;
        public int Age;
        Employee(String name, String position,
                 String salary, int age)
        {
            this.name = name;
            this.position = position;
            this.salary = salary;
            this.Age = age;
        }
        @Override
        public String toString()
        {
            return "Employee [name=" + name + ", position="
                + position + ", salary=" + salary
                + ", Age=" + Age + "]";
        }
    }

    // Main Method
    public static void main(String[] args)
    {
        GFG gfg = new GFG();
        try {
            gfg.PutDemo();
        }
        catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Output:

Details of Employees:
Employee [name=Ranjeet, position=Tester, salary=29000, Age=27]
Employee [name=Sanjeet, position=Manager, salary=98000, Age=34]
Employee [name=Karan, position=Analyst, salary=44000, Age=30]

Program 3: To show NullPointerException thrown by put() method 

Java

// Java Program Demonstrate put(E e)
// method of LinkedBlockingQueue

import java.util.concurrent.LinkedBlockingQueue;

public class GFG {

    public static void main(String[] args)
        throws InterruptedException
    {
        // define capacity of LinkedBlockingQueue
        int capacityOfQueue = 4;

        // create object of LinkedBlockingQueue
        LinkedBlockingQueue<String> linkedQueue
            = new LinkedBlockingQueue<String>(capacityOfQueue);

        // try to put null value in put method
        try {
            linkedQueue.put(null);
        }
        catch (Exception e) {
            // print error details
            System.out.println("Exception: " + e);
        }
    }
}

Output:

Exception: java.lang.NullPointerException

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