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-   -   File Crashes on Opening - NullPointerException - Alice 3 (http://www.alice.org/community/showthread.php?t=11280)

wbarnum 09-02-2015 10:13 AM

File Crashes on Opening - NullPointerException - Alice 3
 
3 Attachment(s)
I've had a few students come to me with the issue of Alice 3.25 for Windows crashing immediately upon opening their file with a NullPointerException.

I can't see or manipulate the scene or the code, so I have no way to evaluate what the problem might be.

The only [URL="http://www.alice.org/community/showthread.php?t=9926&highlight=NullPointerException"]similar posts[/URL] that I can find deal with Alice 2, so I don't know if the cause is related.

I have attached three samples of files that display this behavior.

If anyone else experiences this problem, I would be interested to hear about it.

MrMoke 09-03-2015 07:30 AM

Nope- They didn't load/work for me either. A lot of factors come into play here. Best advice I could give the students is to take the projects one step at a time.
1) Start a new project, and save it as Projectname01.
2) Add a functional piece to the project, and if it works, save it as Projectname02.
3) If, however, you have added code, and it crashes with the dreaded Error Screen, you can always back up to the previous version and try again.
4) If you're satisfied the newer version works, you can always delete the older ones and move forward.

wbarnum 09-03-2015 01:31 PM

[QUOTE=MrMoke;56742]Nope- They didn't load/work for me either. A lot of factors come into play here. Best advice I could give the students is to take the projects one step at a time.
1) Start a new project, and save it as Projectname01.
2) Add a functional piece to the project, and if it works, save it as Projectname02.[/QUOTE]

Thank you. This is good advice. I am going to instruct all my students to version their projects today.

wbarnum 09-04-2015 09:23 PM

Just going to pass on some information in case it might help someone else who is having the same problem.

Don Slater suggested that students may be encountering the angry queen and just ignoring the message. If they continue working, it may cause the file to become corrupted.

I could see that some of my students might use the "silently fail" feature and that this might lead to more problems. I'm going to specifically warn them against this.


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