Introduce configuration of class loader in SimpleTypeInformationMapper.

We now support configuration of the class loader in SimpleTypeInformationMapper to use a configured class loader instead of falling always back to the default/contextual class loader. In arrangements where the contextual class loader isn't able to provide access to the desired classes (e.g. parallel Streams, general Fork/Join Thread usage) the contextual class loader may not have access to the entity types. By implementing BeanClassLoaderAware, we can now propagate a configured class loader.

Closes #2508

src/test/java/org/springframework/data/convert/DefaultTypeMapperUnitTests.java

@@ -18,6 +18,8 @@ package org.springframework.data.convert;
 import static org.assertj.core.api.Assertions.*;
 import static org.mockito.Mockito.*;
 
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.Collections;
 import java.util.Map;
 
@@ -29,6 +31,7 @@ import org.mockito.junit.jupiter.MockitoExtension;
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
 
+import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.data.mapping.Alias;
 import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.data.util.TypeInformation;
@@ -47,7 +50,7 @@ class DefaultTypeMapperUnitTests {
 	static final Alias ALIAS = Alias.of(String.class.getName());
 
 	@Mock TypeAliasAccessor<Map<String, String>> accessor;
-	@Mock TypeInformationMapper mapper;
+	@Mock(extraInterfaces = BeanClassLoaderAware.class) TypeInformationMapper mapper;
 
 	DefaultTypeMapper<Map<String, String>> typeMapper;
 	Map<String, String> source;
@@ -102,6 +105,15 @@ class DefaultTypeMapperUnitTests {
 		assertThat(typeInformation.getProperty("field").getType()).isEqualTo(Character.class);
 	}
 
+	@Test // GH-2508
+	void configuresClassLoaderOnTypeInformationMapper() {
+
+		ClassLoader loader = new URLClassLoader(new URL[0]);
+		typeMapper.setBeanClassLoader(loader);
+
+		verify((BeanClassLoaderAware) mapper).setBeanClassLoader(loader);
+	}
+
 	static class TypeWithAbstractGenericType<T> {
 		AbstractBar<T> abstractBar;
 	}

src/test/java/org/springframework/data/convert/SimpleTypeInformationMapperUnitTests.java

@@ -18,6 +18,8 @@ package org.springframework.data.convert;
 import static org.assertj.core.api.Assertions.*;
 
 import org.junit.jupiter.api.Test;
+
+import org.springframework.data.classloadersupport.HidingClassLoader;
 import org.springframework.data.mapping.Alias;
 import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.data.util.TypeInformation;
@@ -26,10 +28,11 @@ import org.springframework.data.util.TypeInformation;
  * Unit tests for {@link SimpleTypeInformationMapper}.
  *
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 class SimpleTypeInformationMapperUnitTests {
 
-	TypeInformationMapper mapper = new SimpleTypeInformationMapper();
+	SimpleTypeInformationMapper mapper = new SimpleTypeInformationMapper();
 
 	@Test
 	void resolvesTypeByLoadingClass() {
@@ -41,6 +44,16 @@ class SimpleTypeInformationMapperUnitTests {
 		assertThat(type).isEqualTo(expected);
 	}
 
+	@Test // GH-2508
+	void usesConfiguredClassloader() {
+
+		mapper.setBeanClassLoader(HidingClassLoader.hide(SimpleTypeInformationMapperUnitTests.class));
+		TypeInformation<?> type = mapper
+				.resolveTypeFrom(Alias.of("org.springframework.data.convert.SimpleTypeInformationMapperUnitTests.User"));
+
+		assertThat(type).isNull();
+	}
+
 	@Test
 	void returnsNullForNonStringKey() {
 		assertThat(mapper.resolveTypeFrom(Alias.of(new Object()))).isNull();
@@ -63,4 +76,8 @@ class SimpleTypeInformationMapperUnitTests {
 		assertThat(mapper.createAliasFor(ClassTypeInformation.from(String.class)))
 				.isEqualTo(Alias.of(String.class.getName()));
 	}
+
+	static class User {
+
+	}
 }