avoid NPE for definitions without bean class specified

Author: jhoeller

org.springframework.context/src/main/java/org/springframework/context/annotation/ConfigurationClassPostProcessor.java

@@ -166,7 +166,7 @@ public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
 	 * @return whether the candidate qualifies as (any kind of) configuration class
 	 */
 	protected boolean checkConfigurationClassCandidate(BeanDefinition beanDef) {
-		AnnotationMetadata metadata;
+		AnnotationMetadata metadata = null;
 
 		// Check already loaded Class if present...
 		// since we possibly can't even load the class file for this Class.
@@ -175,29 +175,31 @@ protected boolean checkConfigurationClassCandidate(BeanDefinition beanDef) {
 		}
 		else {
 			String className = beanDef.getBeanClassName();
-			try {
-				MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(className);
-				metadata = metadataReader.getAnnotationMetadata();
-			}
-			catch (IOException ex) {
-				if (logger.isDebugEnabled()) {
-					logger.debug("Could not find class file for introspecting factory methods: " + className, ex);
+			if (className != null) {
+				try {
+					MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(className);
+					metadata = metadataReader.getAnnotationMetadata();
+				}
+				catch (IOException ex) {
+					if (logger.isDebugEnabled()) {
+						logger.debug("Could not find class file for introspecting factory methods: " + className, ex);
+					}
+					return false;
 				}
-				return false;
 			}
 		}
 
-		if (metadata.hasAnnotation(Configuration.class.getName())) {
-			beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_FULL);
-			return true;
-		}
-		else if (metadata.hasAnnotation(Component.class.getName())) {
-			beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE);
-			return true;
-		}
-		else {
-			return false;
+		if (metadata != null) {
+			if (metadata.hasAnnotation(Configuration.class.getName())) {
+				beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_FULL);
+				return true;
+			}
+			else if (metadata.hasAnnotation(Component.class.getName())) {
+				beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE);
+				return true;
+			}
 		}
+		return false;
 	}
 
 	/**

org.springframework.context/src/test/java/org/springframework/context/annotation/ConfigurationClassPostProcessorTests.java

@@ -18,7 +18,9 @@
 
 import static org.junit.Assert.*;
 import org.junit.Test;
+import test.beans.TestBean;
 
+import org.springframework.beans.factory.support.ChildBeanDefinition;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 
@@ -42,8 +44,8 @@ public void testEnhancementIsPresentBecauseSingletonSemanticsAreRespected() {
 		beanFactory.registerBeanDefinition("config", new RootBeanDefinition(SingletonBeanConfig.class));
 		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
 		pp.postProcessBeanFactory(beanFactory);
-		Foo foo = (Foo) beanFactory.getBean("foo");
-		Bar bar = (Bar) beanFactory.getBean("bar");
+		Foo foo = beanFactory.getBean("foo", Foo.class);
+		Bar bar = beanFactory.getBean("bar", Bar.class);
 		assertSame(foo, bar.foo);
 	}
 
@@ -63,6 +65,23 @@ public void testAlreadyLoadedConfigurationClasses() {
 		beanFactory.getBean("bar");
 	}
 
+	/**
+	 * Tests whether a bean definition without a specified bean class is handled
+	 * correctly.
+	 */
+	@Test
+	public void testPostProcessorIntrospectsInheritedDefinitionsCorrectly() {
+		DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+		beanFactory.registerBeanDefinition("config", new RootBeanDefinition(SingletonBeanConfig.class));
+		beanFactory.registerBeanDefinition("parent", new RootBeanDefinition(TestBean.class));
+		beanFactory.registerBeanDefinition("child", new ChildBeanDefinition("parent"));
+		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
+		pp.postProcessBeanFactory(beanFactory);
+		Foo foo = beanFactory.getBean("foo", Foo.class);
+		Bar bar = beanFactory.getBean("bar", Bar.class);
+		assertSame(foo, bar.foo);
+	}
+
 
 	@Configuration
 	static class SingletonBeanConfig {