# Jeroo Demo Class File

One of the reasons that I like Jeroo early in the year is that it’s sort of a light version of Java. It’s Java without all the overhead of class files and full method signatures. Want to write a main method, it’s method main(). No public static void main(String[] args) yet. No full class structure.

But, we do need to move to Java pretty quickly. Class structure is a struggle those first few days. What I’ve found works pretty well is to use the following Jeroo.java class file as a connection between Jeroo and Java.

### How’s it work?

Pretty well,  especially early in the year I find myself starting sentences with “Remember in Jeroo how….”.

And, it takes care of quite a few concepts that are tough to grasp early.

Overall class structure. Sure, this is sort of a gimme. But by this point we’ve been making Jeroos for a couple of weeks and this is a good example of the underlying structure.  It also carries over to the idea that we can create multiple instances from a single class file. Jeroo allows up to 4 Jeroo instances and they’ll all use the same class.

Constructors.  These are a tough concept for rookie coders. Being able to show a constructor here and reference back to calling them in Jeroo labs helps a lot. Doesn’t get 100% of the students there, but definitely a majority make the connection.

Public vs private. Getters and setters are confusing early. Having a private  flowers instance variable that can’t be directly accessed works that point. The Jeroo can tell them if it has a flower, but not how many it has. And, flowers isn’t directly settable by anything other than the constructors. Same is true of the row and column instance variables. They’re not accessible at all, but the Jeroo still knows where it is.

void vs return methods.  Some methods are void and just tell the Jeroo do do something like hop or turn. Some ask the Jeroo a question like “do you have any flowers” and wait for the response.

Method overloading. Yeah, we don’t cover this that in depth early in the year, but it’s there. There are 6 different constructors and 2 hop methods.

### Moving On…

What I didn’t expect the first time I used this was that I would keep coming back to it all year long.  Jeroo is a great starting point, and works really well as a starting point and reference later in the year.