Add support for Kotlin value classes.

This commit introduces support for Kotlin Value Classes which are designed for a more expressive domain model to make underlying concepts explicit. Spring Data can now read and write types that define properties using Value Classes.
The support covers reflection based instantiation of Kotlin inline class, nullability and defaulting permutations as well as value classes with generics.

Closes: #1947
Original Pull Request: #2866

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

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2023 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.util;
+
+import kotlin.jvm.JvmClassMappingKt;
+import kotlin.reflect.KCallable;
+import kotlin.reflect.KClass;
+import kotlin.reflect.KMutableProperty;
+import kotlin.reflect.KProperty;
+import kotlin.reflect.jvm.ReflectJvmMapping;
+
+import java.beans.BeanDescriptor;
+import java.beans.BeanInfo;
+import java.beans.IntrospectionException;
+import java.beans.PropertyDescriptor;
+import java.beans.SimpleBeanInfo;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.BeanInfoFactory;
+import org.springframework.core.KotlinDetector;
+import org.springframework.core.Ordered;
+
+/**
+ * {@link BeanInfoFactory} specific to Kotlin types using Kotlin reflection to determine bean properties.
+ *
+ * @author Mark Paluch
+ * @since 3.2
+ * @see JvmClassMappingKt
+ * @see ReflectJvmMapping
+ */
+public class KotlinBeanInfoFactory implements BeanInfoFactory, Ordered {
+
+	@Override
+	public BeanInfo getBeanInfo(Class<?> beanClass) throws IntrospectionException {
+
+		if (!KotlinDetector.isKotlinReflectPresent() || !KotlinDetector.isKotlinType(beanClass)) {
+			return null;
+		}
+
+		KClass<?> kotlinClass = JvmClassMappingKt.getKotlinClass(beanClass);
+		List<PropertyDescriptor> pds = new ArrayList<>();
+
+		for (KCallable<?> member : kotlinClass.getMembers()) {
+
+			if (member instanceof KProperty<?> property) {
+
+				Method getter = ReflectJvmMapping.getJavaGetter(property);
+				Method setter = property instanceof KMutableProperty<?> kmp ? ReflectJvmMapping.getJavaSetter(kmp) : null;
+
+				pds.add(new PropertyDescriptor(property.getName(), getter, setter));
+			}
+		}
+		return new SimpleBeanInfo() {
+			@Override
+			public BeanDescriptor getBeanDescriptor() {
+				return new BeanDescriptor(beanClass);
+			}
+
+			@Override
+			public PropertyDescriptor[] getPropertyDescriptors() {
+				return pds.toArray(new PropertyDescriptor[0]);
+			}
+		};
+	}
+
+	@Override
+	public int getOrder() {
+		return LOWEST_PRECEDENCE - 10; // leave some space for customizations.
+	}
+
+}