sudoku stops when trying to play it in emulator

Hi all,

First I really enjoyed making the sudoku!
The problem I encountered is when running it on the emulator it sets up the puzzle (easy, medium or hard) but when clicking on one of the tiles, there is the message: sudoku has stopped. In the log cat I get the following message:
Invalid property category path: ValidationPropertiesPage (bundle: org.eclipse.wst.xml.ui, propertyPage: org.eclipse.wst.xml.ui.propertyPage.project.validation)

So far I was able to understand the problems I ran into, but this one really got me stuck.

Maybe it could have something to do with the following method:

private void setTile(int x, int y, int value) {
puzzle[y*9 + x] = value;
}

It gave an error in Eclipse that it needed to return a value so I put return in front of the second line, it made the error message go away but may have created this problem?

EDIT: I’ve fixed the problem of the return error, it was a typing error (private int instead of private void).
Unfortunately the sudoku still stops when trying to click on one of the tiles.

I’ve found the problem, after staring very hard at the java code, it turned out to be a problem in the keypad.xml file.