Alice Community

Alice Community (
-   Bugs and Troubleshooting (
-   -   NullPointerException loading world (

wynn 02-17-2013 02:50 PM

NullPointerException loading world
I am getting the following error loading my world:

Unable to load world

Alice version: 2.3 Mac OS X
os.version: 10.7.5
os.arch: x86_64 Java HotSpot(TM) 64-Bit Server VM
java.vm.version: 20.12-b01-434
user.dir: /Applications/

Throwable that caused the error:
at edu.cmu.cs.stage3.alice.core.visualization.ModelVisualization.loadCompleted(
at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(
at edu.cmu.cs.stage3.alice.core.Element.load(
at edu.cmu.cs.stage3.alice.authoringtool.dialog.LoadElementProgressPane.construct(
at edu.cmu.cs.stage3.progress.ProgressPane$

Unfortunately, I cannot attach the world because its size is 26 MB and the upload limit is apparently 20 MB.

Alice also can't load any of the backups of my world.



djslater107 02-18-2013 07:00 AM

Alice World will not load
See this link...


This is a bit technical, but without having access to your world, this is the next best thing.

Good luck!

Don Slater

wynn 02-18-2013 08:57 AM

Thanks for the help. I'll see what I can do.

wynn 02-20-2013 01:13 PM

shrank the world
1 Attachment(s)
I was able to shrink the size of the world to under 20 MB to fit in your upload limits by replacing some of the object textures (texture/image.png) with smaller versions of the same. This world dies with the same error as the original world (NullPointerException), so hopefully I haven't messed anything else up. See attached world. Thanks for any help.

djslater107 02-22-2013 07:39 AM

Null Ptr Exception
I have sent this file to support to see what can be done with it...

It has an exceptionally large number of models in it, which can cause problems for Alice as the size of the world approaches the allocated stack space in the system for the program.

May I ask, did you use the clone tool in the scene editor to create all the models, or did you add each object individually? The clone tool was designed for scene decoration and can sometimes save space when using lots of objects. (It does have limitations, and can cause problems when you try and animate any of the cloned objects.)

Finally, with my students I recommend that they build the basic structure of their world, with a minimal amount of scenery to start, get their animation working, and then start layering in the additional scenery, saving frequently, and with different version numbers, so that if and when they encounter the problem you seem to be experiencing, they can go back to an earlier version.

I will let you know if an when I hear anything.

wynn 02-22-2013 05:06 PM

Clone Tool?
I did use the clone tool when making multiple copies of my objects and thanks for letting me know about making the animations before adding scenery. I hope you can find a solution and I will try to be more aware of problems like this.

aikmin 02-25-2013 08:58 PM

1 Attachment(s)
I removed one of your object visualization model. Alice is giving you that null pointer exception because you had deleted the Item variable from the model.

wynn 02-26-2013 06:06 PM

Alice world working!
My alice world successfully loaded, and I can see witch object was deleted.
Thanks for the help, and I hope you can help in the future.

All times are GMT -5. The time now is 08:04 AM.

Copyright ©2020, Carnegie Mellon University
Alice 2.x 1999-2012, Alice 3.x 2008-2012, Carnegie Mellon University. All rights reserved.