DelayQueue add() method in Java with Examples

// Java program to illustrate the add()
// method in Java

import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

public class GFG {
    public static void main(String args[])
    {
        // Create a DelayQueue instance
        DelayQueue<Delayed> queue = new DelayQueue<Delayed>();

        // Create an instance of Delayed
        Delayed obj = new Delayed() {
            public long getDelay(TimeUnit unit)
            {
                return 24; // some value is returned
            }

            public int compareTo(Delayed o)
            {
                if (o.getDelay(TimeUnit.DAYS) > this.getDelay(TimeUnit.DAYS))
                    return 1;
                else if (o.getDelay(TimeUnit.DAYS) == this.getDelay(TimeUnit.DAYS))
                    return 0;
                return -1;
            }
        };

        // Use the add() method to add obj to
        // the empty DelayQueue instance
        queue.add(obj);

        System.out.println("Size of the queue : " + queue.size());
    }
}

// Java program to illustrate the Exception
// thrown by add() method of
// DelayQueue class

import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

public class GFG {
    public static void main(String args[])
    {
        // Create an instance of DelayQueue
        DelayQueue<Delayed> queue = new DelayQueue<Delayed>();

        // Try to add NULL to the queue
        try {
            queue.add(null);
        } 

        // Catch Exception
        catch (Exception e) {

            // Print Exception raised
            System.out.println(e);
        }
    }
}