Refine assignment flow and use early returns where possible. Cache empty MapSqlParameterSource. Reduce dependency on RelationalMappingContext using a lower-level abstraction signature. Simplify names. Use default value check from Commons. Fix log warning message. Add missing since tags.
Remove superfluous annotations and redundant code. Tweak documentation wording.
Closes#2003
Original pull request: #2005
d0e43be314