CP2003 - Tutorial Twelve: Applet of My Eye

For the twelth and final tutorial we are going to firstly look at some summary questions and then take a look at applets and how easy it is to make an applet out of an application.

Firstly, some quick questions harking back to your early days of CP2003:
- What is the difference between a class and an object?
- What is inheritance and how does Java implement it? Draw a hierarchy scheme for various bank accounts (savings account, cheque account, credit account, passbook account etc.).
- What is the point of Java forcing you to use try/catch blocks?
- What is the point of Java wrapping lots of objects around each other when you are (say) trying to read a file?
- What are access modifiers (public, private, protected) and what part do these play in inheritance?
The programming question for today is firstly to consider an already existing application (start with something slightly simpler like BallMover.java - don't forget to download the picture for the dialog box).
The task now is to convert BallMover.java into an applet. There is a standard way of doing this: Firstly, you will need to use the class JApplet which is like a plain Applet but has its own content pane and a few other niceties. Here's what else you have to do:
1. Remove the class with the main method in it.
2. Inherit from JApplet, not JFrame.
3. Remove the window listener.
4. Remove the call to setSize and instead set the size in the applet's HTML page.
5. Remove the call to setTitle.
Compile your modified code.
You'll need to write an accompanying HTML file (like the one in tutorial nine), and you should point your browser at this HTML file. Note that if the browser you are using is not a very recent version then you should use the program appletviewer which comes with the jdk (run it as appletviewer blah.html).