Sébastien Deleuze opened SPR-15869 and commented

As specified in this custom nullability proposal and as discussed with Jetbrains team, methods overridding parent one with @Nullable return values annotation require the @Nullable annotation to be present at the same level than @Override to get nullable qualifier taken in account in the overridden method.

This is currently not done in most places, so this need to be fixed to get null-safety handled correctly by IDEA and Kotlin.

Issue Links:

• Introduce null-safety of Spring Framework API [SPR-15540] #20099 Introduce null-safety of Spring Framework API
• Revisit nullability annotations towards GA [SPR-15756] #20311 Revisit nullability annotations towards GA

Referenced from: commits 73cf07e, 47a7475