BlockingQueue put() method in Java with examples

The put(E e) method of BlockingQueue interface inserts element passed as parameter to method at the tail of this BlockingQueue, 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 BlockingQueue.

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

Note: The put() method of BlockingQueue has been inherited from the Queue class in Java.
Below programs illustrates put(E e) method of BlockingQueue class:
Program 1:

Java

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

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

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

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

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

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

Output:

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

Program 2:

Java

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

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

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

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

        // Add element to BlockingQueue
        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 BQ
        // Using put(E e)
        BQ.put(emp1);
        BQ.put(emp2);
        BQ.put(emp3);

        System.out.println("Details of Employees:");
        // print details of BQ
        Iterator itr = BQ.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:

Java

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

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.BlockingQueue;

public class GFG {

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

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

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

Output:

Exception: java.lang.NullPointerException

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingQueue.html#put(E)