Improve exception handling and comments

[jordanpadams]

💡 Description

Per comments on this this PR, there is way too much use of the generic exception in this code, and overuse of core java exceptions that make no sense when applying to PDS (e.g. ArrayIndexOutOfBounds exception should not be used when we are talking about overlapping fields in a PDS array data object).

Additionally, per the comment on PR, could use a comment when some values are very PDS domain specific.