Fix warnings

See gh-34409

Author: bclozel

spring-web/src/main/java/org/springframework/http/ProblemDetail.java

@@ -68,6 +68,7 @@ public class ProblemDetail implements Serializable {
 
 	private @Nullable URI instance;
 
+	@SuppressWarnings("serial")
 	private @Nullable Map<String, Object> properties;
 
 

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java

@@ -220,6 +220,8 @@ public String doWork() {
 
 	private static class MyProblemDetail extends ProblemDetail {
 
+		private static final long serialVersionUID = -3036911788793188054L;
+
 		public MyProblemDetail(HttpStatus status) {
 			super(status.value());
 		}

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java

@@ -841,6 +841,8 @@ SimpleBean getSimpleBean() {
 
 	private static class MyProblemDetail extends ProblemDetail {
 
+		private static final long serialVersionUID = 848059476504348430L;
+
 		public MyProblemDetail(HttpStatus status) {
 			super(status.value());
 		}