Trouble Shooting Guide

99% Of All Problems Are Typos!!! Please Double Check!

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Security Exceptions:

These are most often because the applet is running on one server and getting images off some other server. To remedy this, localize everything as much as you can. I don't think it should be a problem if the images are remote, but probably if the applet is remote to your server it's more likely (I'm not real clear on java securities, can you tell?) You shouldn't be running it off of this server anyway. :-)

 

Null Pointer Exceptions:

You're sure it's not a typo? Well then, it's probably a mistake in the

URL's for the images or sounds. Make sure that they are correct and that your securities for these files are set correctly (in UNIX usually something like 'chmod 755 filename'.) Also I think that relative path names do NOT work, so you can try them, but probably you need the full http://www.blah.com/~you/java/file.jpg URL...

 

Class Format Errors:

These come when folks get the class file from the actual file link

(which actually no longer exists) and not the .zip or .tar files and their browser corrupts the data stream. It will look right, but java can't load it. Get the .zip or .tar from the main page, decompress (emotionally and virtually) and it will probably work a lot better.

 

Transparency Problems:

See the discussion in the user's guide about this for general inquiries

regarding transparency. One option is to use javascript for your

highlighting buttons. If you have a simple button I think that you can do basically exactly the same thing as my applet (without a lot of the overhead.) I think you can even get it to play sounds (though not as invisibly perhaps... i.e. I think a window would have to come up for it, but I'm not sure...) You may not be able to get all four button states though, I'm not sure, but you could have transparency. A partially complete example (open the SELECTOR.) I also do not think that Micro$oft Internet Explorer yet supports javascript (it's one of the biggest netscapeisms there are) so that may be a factor.

 

Image Quality Problems:

Dithering and poor palette selection is something out of my hands (at

general rule of thumb is that if you get poor image results (make sure to try it on different machines with different browsers, as always with web developing) go into an image-processing program and dither it or reduce the quality or whatever and use that image: the program will probably do a much better job of the reduction than the browser, and your problem may be solved.

 

Button Linking Doesn't Seem To Work; No Errors Reported:

Some problems with Netscape have come up. Sometimes it just won't follow the link until a good bit after... Also right now when the link is actiated the last mouseexit sent to the applet is "ignored" in a sense so that no extra normal sounds will play when the new page comes up. If there is no link however, moving the mouse off the activated button will play the normal sound. I suppose that's the way it should be. :-)

 

Button State Errors - "Why did it do that?":

Netscape 3.0b5aGold (& other versions, I think) does not send mouseUp's to the Java window that don't occur within the java applet. They are aware of this bug. This causes it to be permanently in select mode (no highlight) after a mouse down is received in the window until a mouseUp in the window at which time it will link/whatever... Netscape 3.0 seems to handle clicks

and drags improperly so that clicking (and holding) on the button, dragging off and then dragging on again will not bring up the select image as it should... In fact it won't even bring up the highlighted image. But then when you release it will "activate" for a brief second and then go to normal and then highlight, all very rapidly. (You may need to try several times to see this actually happen as redraws are not always updated...) Clicking outside of the button and dragging on will not change the image either... I don't know if they are aware of this problem...

 

"My Sounds Don't Work":

Remember that java only supports 8k mono Sun u-law compressed format right now.