The addmoney method is defined a way we've n - java help on CodeGym

Before I even get started trying to figure this out, CodeGym has once again given us code using a structure they haven't taught us yet. I would like to know what is going on before I do anything else:

private static Thread addMoney = new Thread()
{
    @Override
    public void run()
    {
        while (!isStopped)
        {
            account.deposit("1000");            // Make a deposit
            try
            {
                Thread.sleep(1000);
            }
            catch (InterruptedException e)
            {
                break;
            }
        }
    }
};

What I don't understand is the use of brackets after Thread(). Usually there would be a semi-colon ending the statement there, and if you need to override the run() method you would create a new class that extends Thread. That's what we've done before. Can someone explain what's going on here? EDIT: Is the above code functionally the same thing as:

private Thread addMoney = new myThread();

public static class myThread extends Thread
{
        @Override
        public void run()
        {
            while (!isStopped)
            {
                account.deposit("1000");            // Make a deposit
                try
                {
                    Thread.sleep(1000);
                }
                catch (InterruptedException e)
                {
                    break;
                }
            }
        }
}

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Guadalupe Gagnon

Level 37 , Tampa, United States

28 September 2021, 11:52

The first bit of code is what is called an anonymous class. You are correct in what you have found where those 2 bits of code are exactly the same. Anonymous classes are short hand ways of declaring a class right where you need it rather than in a separate class (and typically separate file). As for the code not being introduced yet. a) it isn't the only way to solve this task b) my theory is that the "correct" solves they provide were just skimmed from the accepted solutions that students have passed in. I have seen solves that were exactly the way I solved a task. If this is the case then you have to realize that some students have way more experience in programming then others.

Gellert Varga

Level 23 , Szekesfehervar, Hungary

28 September 2021, 09:55

I get annoyed when unknown codes are thrown in, too... Nobody explained it to me, I just had to figure it out. So maybe a much more experienced student will be able to answer your question much smarter than I can... But this is what I think: The two codes have exactly the same function. The only difference, I think, is that in the second case you wrote a new class (myThread), and in the first code you didn't. In the first case, you probably only need a single thread-object, and you can do it that way, directly overriding the run method. I assume the second case is more appropriate if you want to create multiple Thread objects with the same run method. Make a note of this new way of creating objects, it will be used from time to time by CG, but there is no explanation in the lessons on it yet. ((P.S: you left out the 'static' word in line 1 of the second code! That should be there. Then the second version will have exactly the same function as the first version.))

Thomas

Level 41 , Bayreuth, Germany

28 September 2021, 14:12

Can you remember when you asked what a method reference is? This here is the base for that. Justin already nailed it to the point. This here is a anonymous class. When you just need one implementation of an extended class (eg. of an abstract class or maybe even an interface) then you can write the implementation and and assign an instance to a variable right away. That's pretty cool if some method you use takes an interface as parameter. Instead of first implementing the interface, then creating an instance and last but not least passing that instance as argument you can do that alltogether with a just a anonymous class as argument (or you shorten that even more to a lambda or a method reference). I read a lil bit about GUIs (and wrote some code as well). Comes in handy here, too. You'll learn that here ~lvl 24-25 in the multithreading quest. When working with streams lamdas and method refernces have their strength, too (and of course anon. classes as their base).

The addmoney method is defined a way we've never seen before, can someone explain?