From 43b9f29ee8a34530a01b7d0b5ca0a53e0d01988d Mon Sep 17 00:00:00 2001
From: Oliver Drotbohm <odrotbohm@vmware.com>
Date: Sat, 3 Apr 2021 17:04:55 +0200
Subject: [PATCH] #1507 - Fix potential NullPointerException in
 Jsr303AwarePropertyMetadata.

We now check whether we could really load `@Range`, which is only available in Hibernate Validator. An arrangement in which the Validation API JAR is on the classpath but not Hibernate Validator would let us end up with the relevant instance being `null` and need a check for before being handed into code that requires the type to not be `null`.
---
 .../hateoas/mediatype/PropertyUtils.java      | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/main/java/org/springframework/hateoas/mediatype/PropertyUtils.java b/src/main/java/org/springframework/hateoas/mediatype/PropertyUtils.java
index 85aedfef..e3b1676f 100644
--- a/src/main/java/org/springframework/hateoas/mediatype/PropertyUtils.java
+++ b/src/main/java/org/springframework/hateoas/mediatype/PropertyUtils.java
@@ -539,7 +539,7 @@ public class PropertyUtils {
 	private static class Jsr303AwarePropertyMetadata extends DefaultPropertyMetadata {
 
 		private static final Optional<Class<? extends Annotation>> LENGTH_ANNOTATION;
-		private static final Class<? extends Annotation> URL_ANNOTATION, RANGE_ANNOTATION;
+		private static final @Nullable Class<? extends Annotation> URL_ANNOTATION, RANGE_ANNOTATION;
 		private static final Map<Class<? extends Annotation>, String> TYPE_MAP;
 
 		static {
@@ -609,10 +609,13 @@ public class PropertyUtils {
 		@Override
 		public Long getMin() {
 
-			Optional<Long> attribute = getAnnotationAttribute(RANGE_ANNOTATION, "min", Long.class);
+			if (RANGE_ANNOTATION != null) {
 
-			if (attribute.isPresent()) {
-				return attribute.get();
+				Optional<Long> attribute = getAnnotationAttribute(RANGE_ANNOTATION, "min", Long.class);
+
+				if (attribute.isPresent()) {
+					return attribute.get();
+				}
 			}
 
 			return getAnnotationAttribute(Min.class, "value", Long.class).orElse(null);
@@ -626,10 +629,13 @@ public class PropertyUtils {
 		@Override
 		public Long getMax() {
 
-			Optional<Long> attribute = getAnnotationAttribute(RANGE_ANNOTATION, "max", Long.class);
+			if (RANGE_ANNOTATION != null) {
 
-			if (attribute.isPresent()) {
-				return attribute.get();
+				Optional<Long> attribute = getAnnotationAttribute(RANGE_ANNOTATION, "max", Long.class);
+
+				if (attribute.isPresent()) {
+					return attribute.get();
+				}
 			}
 
 			return getAnnotationAttribute(Max.class, "value", Long.class).orElse(null);