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dwolfe@osu
08-24-2011, 01:09 PM
I had a student receive the following error message:

Exception in thread "Thread-103" java.lang.NullPointerException
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l$12.run (AuthoringTool.java:1686)


What do we need to do? He has uninstalled and reinstalled Alice 2.2 now. He received this message while trying to save his world.

Mr Kidnapper
08-25-2011, 01:42 AM
It appears that your student's world is a bit messy. Perhaps he left a field or two blank (None or Null) or a freak accident happened when he copy and pasted, causing invalid values in the input boxes, such as rotating an object by 5 seconds instead of revolutions (Though this usually does not throw an error.)

Dj Tech42
08-25-2011, 08:09 PM
I think it means that the mouse distance function isn't working. It doesn't detect the pointer, so it says "NullPointer."

patrick3437
08-25-2011, 10:24 PM
Wanted to chime in here, I am the one receiving the error. I started getting this when I completed the first tutorial out of the book, which is placing two objects into a world and changing the opacity of one and the color of the other, after doing so the error occurs when I am trying to save the world.

arty-fishL
08-26-2011, 11:21 AM
I think it means that the mouse distance function isn't working. It doesn't detect the pointer, so it says "NullPointer."
No, a null pointer error is when a null (none) value is returned and was not expected or when a function fails to respond correctly or when a value that should exist does not.

Wanted to chime in here, I am the one receiving the error. I started getting this when I completed the first tutorial out of the book, which is placing two objects into a world and changing the opacity of one and the color of the other, after doing so the error occurs when I am trying to save the world.Does this error exist in just this world? Does this world cause the same error on other computers?
If so then your world is screwed, you will have to start again.
5423
If not then please respond and I (and others) can help further.

patrick3437
08-26-2011, 05:08 PM
I have created this world about 15 times, it is really a very simple intro to the program, the first tutorial in my book. This is happening on any world I have tried to make so far. I have been able to save the world and complete other worlds on my mac with no problem, however, on my pc is where I'm running into the error.

aikmin
08-29-2011, 03:34 AM
What is the date of your Alice download. Do you have the latest Aug 5th download?

Your error:
Exception in thread "Thread-103" java.lang.NullPointerException
at edu.cmu.cs.stage3.alice.authoringtool.AuthoringToo l$12.run (AuthoringTool.java:1686)

This error was caused by your Alice world backups. Delete your backup folder and try again.

patrick3437
08-30-2011, 09:24 PM
I deleted the backups, re-created, re-saved and it worked. Thank you very much. Do you think this will continue to occur? And it is the 8/5/2011 download.