Merge pull request #66 from dridi/SPR-9176

* SPR-9176:
  Fix scoped-proxy memory leak w/ @Resource injection

spring-context/src/main/java/org/springframework/context/annotation/CommonAnnotationBeanPostProcessor.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.
@@ -35,6 +35,7 @@ import java.util.LinkedList;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+
 import javax.annotation.PostConstruct;
 import javax.annotation.PreDestroy;
 import javax.annotation.Resource;
@@ -509,9 +510,12 @@ public class CommonAnnotationBeanPostProcessor extends InitDestroyAnnotationBean
 	 */
 	private class ResourceElement extends LookupElement {
 
-		@SuppressWarnings("unused")
 		protected boolean shareable = true;
 
+		private volatile boolean cached = false;
+
+		private volatile Object cachedFieldValue;
+
 		public ResourceElement(Member member, PropertyDescriptor pd) {
 			super(member, pd);
 		}
@@ -546,7 +550,20 @@ public class CommonAnnotationBeanPostProcessor extends InitDestroyAnnotationBean
 
 		@Override
 		protected Object getResourceToInject(Object target, String requestingBeanName) {
-			return getResource(this, requestingBeanName);
+			Object value = null;
+			if (this.cached && this.shareable) {
+				value = this.cachedFieldValue;
+			}
+			synchronized (this) {
+				if (!this.cached) {
+					value = getResource(this, requestingBeanName);
+					if (value != null && this.shareable) {
+						this.cachedFieldValue = value;
+						this.cached = true;
+					}
+				}
+			}
+			return value;
 		}
 	}