Java Compatibility

[Faunis]

Hello. I'm just starting some basic programs from my own computer. (I previously used a school network) I wrote a few small (and sloppily coded) games in Java as applets. But there are some computers I've tried running them on where they simply don't work. Any computer with JCreator installed tends to run them, but other computers don't. Usually, the applet screen shows up as a broken image and the window displays a small message along the bottom, along the lines of a failure to load the applet. (The message varies from computer to computer)

Is this an issue with java compatibility with older computers, with applets in general, or a problem in programming?

[dmikesell]

"Write Once Debug Everywhere"

[bjgil2]

Its an issue with the default version of Java in Windows i.e. really old. I assume JCreator installs a newer version which is why the applets run on those machines.

[walkal]

A year or two ago, Microsoft stopped including its Java Virtual Machine with Windows, so computers bought recently may not have ANY version of Java - it depends on whether the computer manufacturer sees fit to install Java.

[carl]

It would help a lot if you could provide an example error message, and preferably a stack trace.

I'm assuming you are running the applet through a browser. Instructions for enabling the Java console for your browser can be found at: http://www.java.com/en/download/help/5000020900.xml

The instructions for enabling your console may differ if you are running the applet in an older browser. Googling for: enable java console YOUR_BROWSER_VERSION should provide you with instructions.

[GameGlyph]

Also of note is the fact that only Macs running the newest OS (10.4), can use the newest version of Java (1.5). I think the highest Mac 10.3 will go is 1.4.1.

[Faunis]

Thanks! So there are some compatibility issues with newer versions of java and newer windows/older macs. If it's just coded in Java, but doesn't use applets, will I run into similar errors?

Also, should this discourage me from using the language to program games, or is it still worth it to use Java?

[mot]

Also, should this discourage me from using the language to program games, or is it still worth it to use Java?

Up to you. The problems mentioned here can be overcome. You can bundle your own JRE with your software or check for a compatible version and download it if it's not there etc. For Macs with Java 1.4, you can use a tool called Retroweaver, which will convert your version 1.5 .class or .jar files to 1.4.

[carl]

Also, should this discourage me from using the language to program games, or is it still worth it to use Java?

Make sure you consider this question from a marketing perspective as well as a technical one.

Will the person you see playing the game be willing or able to install Java and resolve any problems?

Does your target market already have Java installed?

If you bundle a VM with your game, will the bandwidth costs be too expensive? Will the size of the download / demo turn people off?

Java has worked beautifully for Fall of Rome (http://www.fallofromegame.com). Last week I was able to release a new client with an Artwork overhaul, and all players received the updated version at once without installation / upgrade headaches. That's worth a lot to me :)