Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
The tests work fine. I really don't know how you get to pointer exceptions, when there are none... Maybe try resetting kata trainer?
If you still can't solve it, post your code here, marking it as spoiler, and with proper formatting. (link)
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That's because there are no sample tests (for java and for other languages too).