Don't create PersistentEntity for Nullable wrapper type.

Original pull request: #2394.
Closes #2390.

Author: christophstrobl

src/main/java/org/springframework/data/mapping/context/AbstractMappingContext.java

@@ -30,6 +30,7 @@
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -61,6 +62,7 @@
 import org.springframework.data.spel.ExtensionAwareEvaluationContextProvider;
 import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.data.util.KotlinReflectionUtils;
+import org.springframework.data.util.NullableWrapperConverters;
 import org.springframework.data.util.Optionals;
 import org.springframework.data.util.Streamable;
 import org.springframework.data.util.TypeInformation;
@@ -483,6 +485,9 @@ protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
 		if (simpleTypeHolder.isSimpleType(type.getType())) {
 			return false;
 		}
+		if(NullableWrapperConverters.supports(type.getType())) {
+			return false;
+		}
 
 		return !KotlinDetector.isKotlinType(type.getType()) || KotlinReflectionUtils.isSupportedKotlinClass(type.getType());
 	}
@@ -569,7 +574,19 @@ private void createAndRegisterProperty(Property input) {
 				return;
 			}
 
-			property.getPersistentEntityTypes().forEach(AbstractMappingContext.this::addPersistentEntity);
+			StreamSupport.stream(property.getPersistentEntityTypes().spliterator(), false)
+					.map(it -> {
+						if(it.isNullableWrapper()) {
+							return it.getActualType();
+						}
+						return it;
+					})
+					.filter(it -> {
+
+						boolean shouldCreate = AbstractMappingContext.this.shouldCreatePersistentEntityFor(it);
+						return shouldCreate;
+					})
+					.forEach(AbstractMappingContext.this::addPersistentEntity);
 		}
 
 		protected boolean shouldSkipOverrideProperty(P property) {

src/main/java/org/springframework/data/util/TypeDiscoverer.java

@@ -309,6 +309,10 @@ public TypeInformation<?> getActualType() {
 			return getComponentType();
 		}
 
+		if (isNullableWrapper()) {
+			return getComponentType();
+		}
+
 		return this;
 	}
 
@@ -384,6 +388,10 @@ protected TypeInformation<?> doGetComponentType() {
 			return getTypeArgument(Iterable.class, 0);
 		}
 
+		if(isNullableWrapper()) {
+			return getTypeArgument(rawType, 0);
+		}
+
 		List<TypeInformation<?>> arguments = getTypeArguments();
 
 		return arguments.size() > 0 ? arguments.get(0) : null;

src/main/java/org/springframework/data/util/TypeInformation.java

@@ -273,4 +273,9 @@ default TypeInformation<?> getRequiredSuperTypeInformation(Class<?> superType) {
 	default boolean isSubTypeOf(Class<?> type) {
 		return !type.equals(getType()) && type.isAssignableFrom(getType());
 	}
+
+	default boolean isNullableWrapper() {
+		return NullableWrapperConverters.supports(getType());
+	}
+
 }