Inject the class loader from the parent context into the child context (#1098)

Author: tommyk-gears

spring-cloud-context/src/main/java/org/springframework/cloud/context/named/NamedContextFactory.java

@@ -29,9 +29,11 @@
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.env.MapPropertySource;
@@ -45,6 +47,7 @@
  * @param <C> specification
  * @author Spencer Gibb
  * @author Dave Syer
+ * @author Tommy Karlsson
  */
 // TODO: add javadoc
 public abstract class NamedContextFactory<C extends NamedContextFactory.Specification>
@@ -110,7 +113,25 @@ protected AnnotationConfigApplicationContext getContext(String name) {
 	}
 
 	protected AnnotationConfigApplicationContext createContext(String name) {
-		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		AnnotationConfigApplicationContext context;
+		if (this.parent != null) {
+			// jdk11 issue
+			// https://github.com/spring-cloud/spring-cloud-netflix/issues/3101
+			// https://github.com/spring-cloud/spring-cloud-openfeign/issues/475
+			DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+			if (parent instanceof ConfigurableApplicationContext) {
+				beanFactory.setBeanClassLoader(
+						((ConfigurableApplicationContext) parent).getBeanFactory().getBeanClassLoader());
+			}
+			else {
+				beanFactory.setBeanClassLoader(parent.getClassLoader());
+			}
+			context = new AnnotationConfigApplicationContext(beanFactory);
+			context.setClassLoader(this.parent.getClassLoader());
+		}
+		else {
+			context = new AnnotationConfigApplicationContext();
+		}
 		if (this.configurations.containsKey(name)) {
 			for (Class<?> configuration : this.configurations.get(name).getConfiguration()) {
 				context.register(configuration);
@@ -129,9 +150,6 @@ protected AnnotationConfigApplicationContext createContext(String name) {
 		if (this.parent != null) {
 			// Uses Environment from parent as well as beans
 			context.setParent(this.parent);
-			// jdk11 issue
-			// https://github.com/spring-cloud/spring-cloud-netflix/issues/3101
-			context.setClassLoader(this.parent.getClassLoader());
 		}
 		context.setDisplayName(generateDisplayName(name));
 		context.refresh();

spring-cloud-context/src/test/java/org/springframework/cloud/context/named/NamedContextFactoryTests.java

@@ -18,17 +18,26 @@
 
 import java.util.Arrays;
 import java.util.Map;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.util.ClassUtils;
 
 import static org.assertj.core.api.BDDAssertions.then;
 
 /**
  * @author Spencer Gibb
+ * @author Tommy Karlsson
  */
 public class NamedContextFactoryTests {
 
@@ -37,6 +46,10 @@ public void testChildContexts() {
 		AnnotationConfigApplicationContext parent = new AnnotationConfigApplicationContext();
 		parent.register(BaseConfig.class);
 		parent.refresh();
+		testChildContexts(parent);
+	}
+
+	private void testChildContexts(GenericApplicationContext parent) {
 		TestClientFactory factory = new TestClientFactory();
 		factory.setApplicationContext(parent);
 		factory.setConfigurations(Arrays.asList(getSpec("foo", FooConfig.class), getSpec("bar", BarConfig.class)));
@@ -79,6 +92,10 @@ public void testChildContexts() {
 		then(fooContext.getClassLoader()).as("foo context classloader does not match parent")
 				.isSameAs(parent.getClassLoader());
 
+		then(fooContext.getBeanFactory().getBeanClassLoader())
+				.as("foo context bean factory classloader does not match parent")
+				.isSameAs(parent.getBeanFactory().getBeanClassLoader());
+
 		Assertions.assertThat(fooContext).hasFieldOrPropertyWithValue("customClassLoader", true);
 
 		factory.destroy();
@@ -88,10 +105,39 @@ public void testChildContexts() {
 		then(barContext.isActive()).as("bar context wasn't closed").isFalse();
 	}
 
+	@Test
+	void testBadThreadContextClassLoader() throws InterruptedException, ExecutionException, TimeoutException {
+		AnnotationConfigApplicationContext parent = new AnnotationConfigApplicationContext();
+		parent.setClassLoader(ClassUtils.getDefaultClassLoader());
+		parent.register(BaseConfig.class);
+		parent.refresh();
+
+		ExecutorService es = Executors.newSingleThreadExecutor(r -> {
+			Thread t = new Thread(r);
+			t.setContextClassLoader(new ThrowingClassLoader());
+			return t;
+		});
+
+		es.submit(() -> this.testChildContexts(parent)).get(5, TimeUnit.SECONDS);
+	}
+
 	private TestSpec getSpec(String name, Class<?> configClass) {
 		return new TestSpec(name, new Class[] { configClass });
 	}
 
+	static class ThrowingClassLoader extends ClassLoader {
+
+		ThrowingClassLoader() {
+			super(null);
+		}
+
+		@Override
+		public Class<?> loadClass(String name) throws ClassNotFoundException {
+			throw new ClassNotFoundException(name);
+		}
+
+	}
+
 	static class TestClientFactory extends NamedContextFactory<TestSpec> {
 
 		TestClientFactory() {
@@ -147,6 +193,7 @@ static class Baz {
 
 	}
 
+	@ConditionalOnClass(Object.class)
 	static class FooConfig {
 
 		@Bean