DATAJPA-1250 - Inspect repository interfaces in isolated classloader.

We now load repository interfaces for configuration inspection (i.e. for strict mode verification) within an isolated, throw-away classloader if Spring Instrumentation or EclipseLink are on the class path. Loading interfaces and hence domain classes in an isolated classloader does not prevent load-time weaving during EntityManagerFactoryBean initialization since the domain class wasn't loaded by the application classloader.

src/main/java/org/springframework/data/jpa/repository/config/InspectionClassLoader.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 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
+ *
+ *      http://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.jpa.repository.config;
+
+import org.springframework.instrument.classloading.ShadowingClassLoader;
+
+/**
+ * Disposable {@link ClassLoader} used to inspect user-code classes within an isolated class loader without preventing
+ * class transformation at a later time.
+ *
+ * @author Mark Paluch
+ * @since 2.1
+ */
+class InspectionClassLoader extends ShadowingClassLoader {
+
+	/**
+	 * Create a new {@link InspectionClassLoader} instance.
+	 *
+	 * @param parent the parent classloader.
+	 */
+	InspectionClassLoader(ClassLoader parent) {
+
+		super(parent, true);
+
+		excludePackage("org.springframework.");
+	}
+}

src/main/java/org/springframework/data/jpa/repository/config/JpaRepositoryConfigExtension.java

@@ -17,12 +17,16 @@ package org.springframework.data.jpa.repository.config;
 
 import static org.springframework.data.jpa.repository.config.BeanDefinitionNames.*;
 
+import lombok.experimental.UtilityClass;
+
 import java.lang.annotation.Annotation;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.LinkedHashSet;
 import java.util.Locale;
 import java.util.Optional;
+import java.util.Set;
 
 import javax.persistence.Entity;
 import javax.persistence.MappedSuperclass;
@@ -35,6 +39,7 @@ import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.annotation.AnnotationConfigUtils;
 import org.springframework.core.annotation.AnnotationAttributes;
+import org.springframework.core.io.ResourceLoader;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
 import org.springframework.data.jpa.repository.JpaRepository;
@@ -47,6 +52,7 @@ import org.springframework.data.repository.config.RepositoryConfigurationSource;
 import org.springframework.data.repository.config.XmlRepositoryConfigurationSource;
 import org.springframework.lang.Nullable;
 import org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -183,6 +189,19 @@ public class JpaRepositoryConfigExtension extends RepositoryConfigurationExtensi
 		registerIfNotAlreadyRegistered(contextDefinition, registry, JPA_CONTEXT_BEAN_NAME, source);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#getConfigurationInspectionClassLoader(org.springframework.core.io.ResourceLoader)
+	 */
+	protected ClassLoader getConfigurationInspectionClassLoader(ResourceLoader loader) {
+
+		ClassLoader classLoader = loader.getClassLoader();
+
+		return classLoader != null && LazyJvmAgent.isActive(loader.getClassLoader())
+				? new InspectionClassLoader(loader.getClassLoader())
+				: loader.getClassLoader();
+	}
+
 	/**
 	 * Creates an anonymous factory to extract the actual {@link javax.persistence.EntityManager} from the
 	 * {@link javax.persistence.EntityManagerFactory} bean name reference.
@@ -210,4 +229,37 @@ public class JpaRepositoryConfigExtension extends RepositoryConfigurationExtensi
 		Optional<String> entityManagerFactoryRef = config.getAttribute("entityManagerFactoryRef");
 		return entityManagerFactoryRef.orElse("entityManagerFactory");
 	}
+
+	/**
+	 * Utility to determine if a lazy Java agent is being used that might transform classes at a later time.
+	 *
+	 * @author Mark Paluch
+	 * @since 2.1
+	 */
+	@UtilityClass
+	static class LazyJvmAgent {
+
+		private static final Set<String> AGENT_CLASSES;
+
+		static {
+
+			Set<String> agentClasses = new LinkedHashSet<>();
+
+			agentClasses.add("org.springframework.instrument.InstrumentationSavingAgent");
+			agentClasses.add("org.eclipse.persistence.internal.jpa.deployment.JavaSECMPInitializerAgent");
+
+			AGENT_CLASSES = Collections.unmodifiableSet(agentClasses);
+		}
+
+		/**
+		 * Determine if any agent is active.
+		 *
+		 * @return {@literal true} if an agent is active.
+		 */
+		static boolean isActive(@Nullable ClassLoader classLoader) {
+
+			return AGENT_CLASSES.stream() //
+					.anyMatch(agentClass -> ClassUtils.isPresent(agentClass, classLoader));
+		}
+	}
 }

src/test/java/org/springframework/data/jpa/repository/config/InspectionClassLoaderUnitTests.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 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
+ *
+ *      http://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.jpa.repository.config;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link InspectionClassLoader}.
+ *
+ * @author Mark Paluch
+ */
+public class InspectionClassLoaderUnitTests {
+
+	@Test // DATAJPA-1250
+	public void shouldLoadExternalClass() throws ClassNotFoundException {
+
+		InspectionClassLoader classLoader = new InspectionClassLoader(getClass().getClassLoader());
+
+		Class<?> isolated = classLoader.loadClass("org.hsqldb.Database");
+		Class<?> included = getClass().getClassLoader().loadClass("org.hsqldb.Database");
+
+		assertThat(isolated.getClassLoader()).isSameAs(classLoader).isNotSameAs(getClass().getClassLoader());
+		assertThat(isolated).isNotEqualTo(included);
+	}
+}

src/test/java/org/springframework/data/jpa/repository/config/JpaRepositoryConfigExtensionUnitTests.java

@@ -39,14 +39,17 @@ import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigUtils;
+import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.data.repository.config.RepositoryConfigurationExtension;
 import org.springframework.data.repository.config.RepositoryConfigurationSource;
+import org.springframework.instrument.classloading.ShadowingClassLoader;
 import org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor;
 
 /**
  * Unit tests for {@link JpaRepositoryConfigExtension}.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 @RunWith(MockitoJUnitRunner.class)
 public class JpaRepositoryConfigExtensionUnitTests {
@@ -110,6 +113,40 @@ public class JpaRepositoryConfigExtensionUnitTests {
 		factoryBean.createInstance().afterPropertiesSet();
 	}
 
+	@Test // DATAJPA-1250
+	public void shouldUseInspectionClassLoader() {
+
+		JpaRepositoryConfigExtension extension = new JpaRepositoryConfigExtension();
+		ClassLoader classLoader = extension.getConfigurationInspectionClassLoader(new GenericApplicationContext());
+
+		assertThat(classLoader, is(instanceOf(InspectionClassLoader.class)));
+	}
+
+	@Test // DATAJPA-1250
+	public void shouldNotUseInspectionClassLoaderWithoutEclipseLink() {
+
+		ShadowingClassLoader shadowingClassLoader = new ShadowingClassLoader(getClass().getClassLoader(), false) {
+
+			@Override
+			public Class<?> loadClass(String name) throws ClassNotFoundException {
+
+				if (name.startsWith("org.springframework.instrument.") || name.startsWith("org.eclipse.")) {
+					throw new ClassNotFoundException("Excluded: " + name);
+				}
+
+				return getClass().getClassLoader().loadClass(name);
+			}
+		};
+
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.setClassLoader(shadowingClassLoader);
+
+		JpaRepositoryConfigExtension extension = new JpaRepositoryConfigExtension();
+		ClassLoader classLoader = extension.getConfigurationInspectionClassLoader(context);
+
+		assertThat(classLoader, is(not(instanceOf(InspectionClassLoader.class))));
+	}
+
 	private void assertOnlyOnePersistenceAnnotationBeanPostProcessorRegistered(DefaultListableBeanFactory factory,
 			String expectedBeanName) {