Comments

At various points, I am going to leave "comments" in the code. Comments are parts of the code that are solely there for a human to be able to read as an explanation and can be written in regular words.

public class Main {
    public static void main(String[] args) {
        // This prints hello world!
        System.out.println("Hello, World!");
    }
}

The rules for this are that if you see a //, everything after that in the same line is ignored.

If you put // in front of something that is "code" and not an English explanation we colloquially call that "commenting out" the line.

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
        // The line that prints out goodbye is "commented out"
        // System.out.println("Goodbye!");
    }
}

You might want to do that at various points where you want to see what happens if you "turn off" parts of the code.

If you put /* in the code then everything up until the next */ will be treated as a comment. The distinction here is that this style of comment can span multiple lines.

public class Main {
    public static void main(String[] args) {
        /*
            I have eaten
            the plums
            that were in
            the icebox
            and which
            you were probably
            saving
            for breakfast
            Forgive me
            they were delicious
            so sweet
            and so cold
        */
        System.out.println("Hello, World!");
    }
}

So that's a mechanism you will see me use and you can use yourself however you see fit.