Docker + Checkstyles

Hi everyone. I am trying to create a simple docker instance that runs checkstyles on my java code.

I have added it to our existing android docker builder. However when the checkstyles jar finishes, finds thousands of issues (flagged as warnings), it does not exist, as I had hopped. What might be the best way to go about seeing there were warnings and returning a exit code?

CMD java -jar ./styleguide/checkstyle-7.7-all.jar -c ./styleguide/checkstyle-master/src/main/resources/google_checks.xml .

Edit. Got it to output errors now. But still not evoking a non zero on CLI.

Audit done.
Checkstyle ends with 118625 errors.

echo $?