PriorityBlockingQueue put() method in Java

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

import java.util.concurrent.PriorityBlockingQueue;

public class GFG {
    public static void main(String[] args)
    {

        // create object of PriorityBlockingQueue
        PriorityBlockingQueue<Integer> pbq
            = new PriorityBlockingQueue<Integer>();

        // Add element using put() method
        pbq.put(1);
        pbq.put(2);
        pbq.put(3);
        pbq.put(4);

        // print elements of queue
        System.out.println("Queue: " + pbq);
    }
}

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

import java.util.concurrent.PriorityBlockingQueue;

public class GFG {
    public static void main(String[] args)
    {

        // create object of PriorityBlockingQueue
        PriorityBlockingQueue<String> pbq
            = new PriorityBlockingQueue<String>();

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