OZG-4717 Add NonNullApi annotation

src/main/java/de/ozgcloud/admin/RootModelAssembler.java

@@ -28,10 +28,12 @@ import org.springframework.hateoas.server.RepresentationModelAssembler;
 import org.springframework.hateoas.server.mvc.WebMvcLinkBuilder;
 import org.springframework.stereotype.Component;
 
+import io.micrometer.common.lang.NonNullApi;
 import lombok.RequiredArgsConstructor;
 
 @Component
 @RequiredArgsConstructor
+@NonNullApi
 class RootModelAssembler implements RepresentationModelAssembler<Root, EntityModel<Root>> {
 	static final String REL_CONFIGURATION = "configuration";
 

src/test/java/de/ozgcloud/admin/errorhandling/TestErrorController.java

@@ -37,10 +37,12 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 import de.ozgcloud.common.errorhandling.TechnicalException;
+import io.micrometer.common.lang.NonNullApi;
 
 @RestController
 @RequestMapping("/test-error")
-public class TestErrorController {
+@NonNullApi
+class TestErrorController {
 
 	@FunctionalInterface
 	interface ExceptionProducer {