From b79260a01731c3539ab6a0f29996d06a8f93b1dd Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <jhoeller@vmware.com>
Date: Tue, 25 Sep 2012 12:50:10 +0200
Subject: [PATCH] Fixed potential race condition in concurrent calling of
 autowired methods on a prototype bean

Autowired methods might have been skipped on subsequent creation of further bean instances due to the 'skip' flag set to false outside of the synchronized block, with another thread entering the block and setting the flag to true in the meantime.

Issue: SPR-9806
---
 .../factory/annotation/InjectionMetadata.java | 55 +++++++++++--------
 1 file changed, 32 insertions(+), 23 deletions(-)

diff --git a/org.springframework.beans/src/main/java/org/springframework/beans/factory/annotation/InjectionMetadata.java b/org.springframework.beans/src/main/java/org/springframework/beans/factory/annotation/InjectionMetadata.java
index 4a1733de30..c7fa84a72a 100644
--- a/org.springframework.beans/src/main/java/org/springframework/beans/factory/annotation/InjectionMetadata.java
+++ b/org.springframework.beans/src/main/java/org/springframework/beans/factory/annotation/InjectionMetadata.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -54,17 +54,22 @@ public class InjectionMetadata {
 
 
 	public InjectionMetadata(Class targetClass, Collection<InjectedElement> elements) {
-		this.injectedElements = Collections.synchronizedSet(new LinkedHashSet<InjectedElement>());
-		for (InjectedElement element : elements) {
-			if (logger.isDebugEnabled()) {
-				logger.debug("Found injected element on class [" + targetClass.getName() + "]: " + element);
+		if (!elements.isEmpty()) {
+			this.injectedElements = Collections.synchronizedSet(new LinkedHashSet<InjectedElement>(elements.size()));
+			for (InjectedElement element : elements) {
+				if (logger.isDebugEnabled()) {
+					logger.debug("Found injected element on class [" + targetClass.getName() + "]: " + element);
+				}
+				this.injectedElements.add(element);
 			}
-			this.injectedElements.add(element);
+		}
+		else {
+			this.injectedElements = Collections.emptySet();
 		}
 	}
 
 	public void checkConfigMembers(RootBeanDefinition beanDefinition) {
-		synchronized(this.injectedElements) {
+		synchronized (this.injectedElements) {
 			for (Iterator<InjectedElement> it = this.injectedElements.iterator(); it.hasNext();) {
 				Member member = it.next().getMember();
 				if (!beanDefinition.isExternallyManagedConfigMember(member)) {
@@ -170,26 +175,30 @@ public class InjectionMetadata {
 		 * affected property as processed for other processors to ignore it.
 		 */
 		protected boolean checkPropertySkipping(PropertyValues pvs) {
-			if (this.skip == null) {
-				if (pvs != null) {
-					synchronized (pvs) {
-						if (this.skip == null) {
-							if (this.pd != null) {
-								if (pvs.contains(this.pd.getName())) {
-									// Explicit value provided as part of the bean definition.
-									this.skip = true;
-									return true;
-								}
-								else if (pvs instanceof MutablePropertyValues) {
-									((MutablePropertyValues) pvs).registerProcessedProperty(this.pd.getName());
-								}
-							}
-						}
+			if (this.skip != null) {
+				return this.skip;
+			}
+			if (pvs == null) {
+				this.skip = false;
+				return false;
+			}
+			synchronized (pvs) {
+				if (this.skip != null) {
+					return this.skip;
+				}
+				if (this.pd != null) {
+					if (pvs.contains(this.pd.getName())) {
+						// Explicit value provided as part of the bean definition.
+						this.skip = true;
+						return true;
+					}
+					else if (pvs instanceof MutablePropertyValues) {
+						((MutablePropertyValues) pvs).registerProcessedProperty(this.pd.getName());
 					}
 				}
 				this.skip = false;
+				return false;
 			}
-			return this.skip;
 		}
 
 		/**