Nullness annotations must not be used on primitive types

Primitive types can never be null therefore using any nullness annotation on them is invalid. Also to prevent that an array is null the syntax needs to be

<element type> <nullness annotation> [], e.g. byte @NotNull []

Something like e.g. @NotNull byte [] is invalid (compare with https://stackoverflow.com/questions/62066166/string-notnull-syntax-causes-notnull-not-applicable-to-type-use-in-in).