@ExceptionHandler resolves nested exceptions

See gh-23380

spring-web/src/main/java/org/springframework/web/method/annotation/ExceptionHandlerMethodResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -134,7 +134,7 @@ public class ExceptionHandlerMethodResolver {
 		if (method == null) {
 			Throwable cause = exception.getCause();
 			if (cause != null) {
-				method = resolveMethodByExceptionType(cause.getClass());
+				method = resolveMethodByThrowable(cause);
 			}
 		}
 		return method;