Injected Map/Collection does not include null bean entries

Issue: SPR-17034

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -1318,7 +1318,13 @@ protected Map<String, Object> findAutowireCandidates(
 	private void addCandidateEntry(Map<String, Object> candidates, String candidateName,
 			DependencyDescriptor descriptor, Class<?> requiredType) {
 
-		if (descriptor instanceof MultiElementDescriptor || containsSingleton(candidateName)) {
+		if (descriptor instanceof MultiElementDescriptor) {
+			Object beanInstance = descriptor.resolveCandidate(candidateName, requiredType, this);
+			if (!(beanInstance instanceof NullBean)) {
+				candidates.put(candidateName, beanInstance);
+			}
+		}
+		else if (containsSingleton(candidateName)) {
 			Object beanInstance = descriptor.resolveCandidate(candidateName, requiredType, this);
 			candidates.put(candidateName, (beanInstance instanceof NullBean ? null : beanInstance));
 		}

spring-beans/src/test/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessorTests.java

@@ -728,9 +728,8 @@ public void testConstructorResourceInjectionWithCollectionAndNullFromFactoryBean
 		ConstructorsCollectionResourceInjectionBean bean = (ConstructorsCollectionResourceInjectionBean) bf.getBean("annotatedBean");
 		assertNull(bean.getTestBean3());
 		assertSame(tb, bean.getTestBean4());
-		assertEquals(2, bean.getNestedTestBeans().size());
-		assertNull(bean.getNestedTestBeans().get(0));
-		assertSame(ntb2, bean.getNestedTestBeans().get(1));
+		assertEquals(1, bean.getNestedTestBeans().size());
+		assertSame(ntb2, bean.getNestedTestBeans().get(0));
 
 		Map<String, NestedTestBean> map = bf.getBeansOfType(NestedTestBean.class);
 		assertNull(map.get("nestedTestBean1"));
@@ -924,12 +923,12 @@ public void testConstructorInjectionWithMap() {
 		bf.registerBeanDefinition("testBean2", tb2);
 
 		MapConstructorInjectionBean bean = (MapConstructorInjectionBean) bf.getBean("annotatedBean");
-		assertEquals(2, bean.getTestBeanMap().size());
+		assertEquals(1, bean.getTestBeanMap().size());
 		assertSame(tb1, bean.getTestBeanMap().get("testBean1"));
 		assertNull(bean.getTestBeanMap().get("testBean2"));
 
 		bean = (MapConstructorInjectionBean) bf.getBean("annotatedBean");
-		assertEquals(2, bean.getTestBeanMap().size());
+		assertEquals(1, bean.getTestBeanMap().size());
 		assertSame(tb1, bean.getTestBeanMap().get("testBean1"));
 		assertNull(bean.getTestBeanMap().get("testBean2"));
 	}