Autolab has problems with non-ASCII characters. In such cases, you may not even be able to view your submission. This is most commonly a result of non-ASCII characters in comments (e.g., smart quotes, copyright symbols, degree symbols) that find there way into the code when the student cuts-and-pastes from another document.

Here is an online tool to check your code for non-ASCII characters: https://pages.cs.wisc.edu/~markm/ascii.html

This is most likely because your code does not conform to the specifications. Common examples include: misnamed methods/functions, a mis-packaged submission, case problems, missing classes/files, and missing or incorrect use of the static keyword.