if raw type is Collection we have to handle it. Whatever type we use would be fnie, using ArrayList for now since it looks the most common. If we don't handle it then we can't ask for Collection<xxx> which would be a pain in a lot of cases
JOHNZON-21 (renamed setter/getter to method), implemented basic null and empty array handling (allow to have nulls in the serialization, allow to have/skip empty arrays in the serialization)