My first Greenfoot/Java simulation

[DickBaldwin]

In case anyone is interested, my first Greenfoot simulation is online at http://greenfootgallery.org/scenarios/173

I mention this because Greenfoot gives us a 2D preview of what Alice 3.0 can be in 3D once we get rid of the pseudo-language, and the full power of Java is exposed to the programmer.

By the way, your browser must support Java 1.5 or later for this applet to run in your browser.

Dick Baldwin
Free Alice tutorials: http://www.dickbaldwin.com/tocalice.htm
Free Scratch tutorials: http://www.dickbaldwin.com/tocHomeSchool.htm
Free Java/C#, etc. tutorials: http://www.dickbaldwin.com/toc.htm

[lanceA]

I'm glad to see others have 'discovered' Greenfoot, Dick. Like all software it has it's place in the grand scheme of learning. :)

[DickBaldwin]

I'm glad to see others have 'discovered' Greenfoot, Dick. Like all software it has it's place in the grand scheme of learning. :)
Here is a link to my new improved Greenfoot scenario about spiders:

http://greenfootgallery.org/scenarios/181

If nothing else, it's a lot of fun and it uses standard Java.

Dick Baldwin
Free Alice tutorials: http://www.dickbaldwin.com/tocalice.htm
Free Scratch tutorials: http://www.dickbaldwin.com/tocHomeSchool.htm
Free Java/C#, etc. tutorials: http://www.dickbaldwin.com/toc.htm

[DrJim]

I'd also strongly recommend anyone interested read the tutorial at http://www.greenfoot.org/doc/tutorial/tutorial.html . This will make it clear, among other things, that you need version 1.5 or higher of the full Java Development Kit (i.e., JDK 1.5) for "Java 5" and not just version 1.5 (or higher) of the Java Run Time Environment (i.e., JRE 1.5).

[DickBaldwin]

I'd also strongly recommend anyone interested read the tutorial at http://www.greenfoot.org/doc/tutorial/tutorial.html . This will make it clear, among other things, that you need version 1.5 or higher of the full Java Development Kit (i.e., JDK 1.5) for "Java 5" and not just version 1.5 (or higher) of the Java Run Time Environment (i.e., JRE 1.5).
I may be wrong about this, and I have no way of testing, but it is my impression that in order to download and run the online applet, all you need is for your browser to be v1.5 or later compatible. I don't believe that requires the JDK; the JRE should suffice.

[DrJim]

your browser to be v1.5 or later compatible ... the JRE should suffice.

Whatever does that mean??

Attached are three screenshots.

1. What I get when I try to view the spiders
2. The directory where JRE 1.5.x is
3. The control panel - which doesn't specifically show JRE 1.5.

(I "canceled" updates on the last since they didn't seem to affect Alice performance - but did use up memory like crazy. - earlier versions were not deleted.)

[DickBaldwin]

When you open the Java Console in your browser, you should see something like the attached image:

Note the information at the very top of the attachment.

When I first started working with Greenfoot, I discovered that I could run Greenfoot applets either locally or from the website using IE but couldn't run them in Firefox.

When I finally tracked down the problem, I discovered that even though Firefox had updated itself many times, and even though Java 1.6 was installed on my computer, Firefox was still running Java 1.4.

After much effort trying to force Firefox to update itself to Java v1.6, I discovered an old copy of Java v1.4 on my computer. When I deleted it and then tried to run a Greenfoot applet, Firefox updated itself to v1.6 and everything has worked well since.

It is also necessary to have Java applets enabled in the browser for any Java applet to be executed.

Hope this helps,
Dick Baldwin

[DrJim]

Hope this helps,


It did - at least to the extent I can now view the video - and you are correct only the JRE is needed. However, apparently it has to be installed as a stand-alone - the embedded version that Alice 2.2 uses wasn't sufficient. A download of the current version (JRE 1.6-7) from the Sun site does seem to work - as usual with Java stuff I'm never 100% sure. :p

As an added note, the recommendation for anyone interested to read the tutorial wasn't just for this issue. It is quite nicely written (for a computer tutorial) and seems quite informative.

[dang]

> as usual with Java stuff I'm never 100% sure.

If you'd like to be 100% sure, point your browser of choice to "http://java.com" -> "Do I have Java?" link and you'll get to something that will report the Java Runtime Edition your browser is running.

Another option is http://www.java.com/en/download/help/testvm.xml

For what it's worth, the Java runtime has been updated in Java SE 6 Update 10 (http://java.sun.com/javase/downloads/ea/6u10/6u10RC.jsp) to address issues that have come up over 12 years of runtime Java stuff. In particular, the plug-in has received quite a bit of attention (https://jdk6.dev.java.net/plugin2/) and now allows you to drag applets out of your browser on to your desktop as stand alone programs among other things.

Hopefully that is helpful to you.

Best regards,

-- DanG

[alicefan]

This is a very helpful thread!

thanks.

Greenfoot's documentation is pretty hard to follow for beginners. Here is something on kidslike.info that tells you how to change the size of the background.
http://www.kidslike.info/choosing_the_size_of_the_background_for_your_green foot_world

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