Use @Nullable and friends?

[Hjdskes]

I believe this will positively impact our code quality, but it will require an inspection of the current code base. Considering there is not that much yet, I think it's worth it on a long term basis. What do you think?

[Balletie]

Also consider using Optional! https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html

There's a Optional#ofNullable method, which returns an empty optional if the given argument is null, and otherwise returns a "filled" Optional.

[Hjdskes]

When scanning the code, we should also apply final wherever possible.