Don't create PersistentEntity for Nullable wrapper type.

Original pull request: #2394.
Closes #2390.

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

@@ -309,6 +309,10 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 			return getComponentType();
 		}
 
+		if (isNullableWrapper()) {
+			return getComponentType();
+		}
+
 		return this;
 	}
 
@@ -384,6 +388,10 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 			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 @@ public interface TypeInformation<S> {
 	default boolean isSubTypeOf(Class<?> type) {
 		return !type.equals(getType()) && type.isAssignableFrom(getType());
 	}
+
+	default boolean isNullableWrapper() {
+		return NullableWrapperConverters.supports(getType());
+	}
+
 }