Cannot use @NotNull with Principal

Signed-off-by: Martin Weise martin.weise@tuwien.ac.at

Closes #512

.docs/changelog.md

@@ -6,6 +6,8 @@ author: Martin Weise
 
 #### Features
 
+* Fixed a bug where validation of missing `Principal` object in Java services caused a 400 error instead of a 401 error
+  in [#512](https://gitlab.phaidra.org/fair-data-austria-db-repository/fda-services/-/issues/512).
 * Refactored internal Java-based testing data that improves test consistency
   in [#510](https://gitlab.phaidra.org/fair-data-austria-db-repository/fda-services/-/issues/510).
 * Added automated dashboard generation for all public databases where each view has an overview of its data and