RootCauseunvalidated

With field injection, Spring populates `mdcConfig` only after the bean is constructed. `mdcAllowedItems = mdcConfig.getAllowedItems()` is initialized during construction (before dependency injection), so it runs with `mdcConfig` still null.

2ef0477c-33c9-42c2-a9d3-c6c822c301b0

With field injection, Spring populates mdcConfig only after the bean is constructed. mdcAllowedItems = mdcConfig.getAllowedItems() is initialized during construction (before dependency injection), so it runs with mdcConfig still null.