JoC #19: Class methods vs instance methods

      If can keep your head when all about you are losing theirs it’s just possible
      you haven’t grasped the situation.
            — Jean Kerr

Today, we’ve got some background stuff to discuss. Not much happening in terms of new functionality to our project, but important (and, no doubt, incredibly interesting) conceptual information.

Why is there sometimes a classname before a method call and sometimes a variable?

I’m sure all of us have had sleepless nights where we’ve been lying awake pondering this question. Today, it shall be answered!

Download video

Even if you’re not that interested in discussion of underlying concepts, but just want to GET STUFF DONE — still, watch this video. You can only become a good programmer (and get stuff done) if you understand what you’re doing.

I really want you not only to copy what I’m showing you, but become able to invent and create your own programs. For this, it’s important to get the concepts.

So, hit start, sit back for a few minutes, and learn something!

Concepts discussed: internal method calls, external method calls, static methods, instance methods 

5 thoughts on “JoC #19: Class methods vs instance methods

  1. Dear Michael
    I just wanted to drop a quick but very big THANK YOU line. I’m teaching Informatics at Gymnasium Goetheschule Hannover, Germany. My class and my fellow teachers love you blog. Please go ahead!!

  2. Hi Marius,

    Thanks for the feedback – glad to hear it! It’s nice to hear that I’ve got some interested listeners out there.

    Und viele Grüße nach Hannover! (Ich bin in Burgdorf aufgewachsen…) Schön zu sehen, dass Greenfoot auch in Deutschland genutzt wird.


  3. Pingback: JOC#18: Adding Mouse Input to Bouncing Balls (inc JOC#19) -

  4. hi , I’m little bit confuse how to make random image for one card if we click in greenfoot can you give way to solve this case

  5. These tutorials are excellent. They are very well explained and quite easy to follow.
    I just wanted to say thank you and keep them going!!

Leave a Reply

Your email address will not be published. Required fields are marked *