Test for missing @NotNull / @Nullable annotations

[ljacqu]

Write a unit test that scans the parameters of methods and constructors, and the return value of methods and that reports any that don't have @NotNull or @Nullable.

To do

• Add org.reflections as a test dependency
• Write a test that collects all classes of ConfigMe
  • Skip classes that end in "Test"
• Collect all method/constructor params and method return values
• Report all instances where neither nullability annotation is used
  • Special case arrays: T @NotNull [] is how the array itself is reported not null. Probably should also check the component if possible?
  • Begs the question what to do with other generic types such as List<String> (vs. List<@NotNull String>)...?

[ljacqu]

Seems impossible to do currently:

• @NotNull and @Nullable have SOURCE retention, so need to use org.reflections or javassist to pick out the values
• org.reflections has no way of returning whether a specific method parameter has an annotation
• javassist has a bug where it thinks @Foo String[] means the array is annotated, while it's supposed to be String @Foo []. This leads to a lot of false positives.