Code Clean Up [DATAJDBC-137]

[spring-projects-issues]

Jens Schauder opened DATAJDBC-137 and commented

• No raw types, prefere X<?> instead
• No warnings, surpress Warning with minimal scope if not otherwise possible
  -proper Nullability annotations.
  -@since in all classes except tests

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Referenced from: commits 0a0e774, d500703, fca2ef6, d0a8af2, eab63d8