Use ConcurrentMap declarations when calling putIfAbsent (for compatibility with JDK 6 and 7)

Issue: SPR-12102

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java

@@ -480,8 +480,7 @@ public Object convertForProperty(Object value, String propertyName) throws TypeM
 		}
 		TypeDescriptor td = cachedIntrospectionResults.getTypeDescriptor(pd);
 		if (td == null) {
-			td = new TypeDescriptor(property(pd));
-			cachedIntrospectionResults.addTypeDescriptor(pd, td);
+			td = cachedIntrospectionResults.addTypeDescriptor(pd, new TypeDescriptor(property(pd)));
 		}
 		return convertForProperty(propertyName, null, value, td);
 	}

spring-beans/src/main/java/org/springframework/beans/CachedIntrospectionResults.java

@@ -27,6 +27,7 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -112,14 +113,14 @@ public class CachedIntrospectionResults {
 	 * Map keyed by Class containing CachedIntrospectionResults, strongly held.
 	 * This variant is being used for cache-safe bean classes.
 	 */
-	static final Map<Class<?>, CachedIntrospectionResults> strongClassCache =
+	static final ConcurrentMap<Class<?>, CachedIntrospectionResults> strongClassCache =
 			new ConcurrentHashMap<Class<?>, CachedIntrospectionResults>(64);
 
 	/**
 	 * Map keyed by Class containing CachedIntrospectionResults, softly held.
 	 * This variant is being used for non-cache-safe bean classes.
 	 */
-	static final Map<Class<?>, CachedIntrospectionResults> softClassCache =
+	static final ConcurrentMap<Class<?>, CachedIntrospectionResults> softClassCache =
 			new ConcurrentReferenceHashMap<Class<?>, CachedIntrospectionResults>(64);
 
 
@@ -186,17 +187,21 @@ static CachedIntrospectionResults forClass(Class<?> beanClass) throws BeansExcep
 		}
 
 		results = new CachedIntrospectionResults(beanClass);
+		ConcurrentMap<Class<?>, CachedIntrospectionResults> classCacheToUse;
+
 		if (ClassUtils.isCacheSafe(beanClass, CachedIntrospectionResults.class.getClassLoader()) ||
 				isClassLoaderAccepted(beanClass.getClassLoader())) {
-			strongClassCache.putIfAbsent(beanClass, results);
+			classCacheToUse = strongClassCache;
 		}
 		else {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Not strongly caching class [" + beanClass.getName() + "] because it is not cache-safe");
 			}
-			softClassCache.putIfAbsent(beanClass, results);
+			classCacheToUse = softClassCache;
 		}
-		return results;
+
+		CachedIntrospectionResults existing = classCacheToUse.putIfAbsent(beanClass, results);
+		return (existing != null ? existing : results);
 	}
 
 	/**
@@ -246,7 +251,7 @@ private static boolean isUnderneathClassLoader(ClassLoader candidate, ClassLoade
 	private final Map<String, PropertyDescriptor> propertyDescriptorCache;
 
 	/** TypeDescriptor objects keyed by PropertyDescriptor */
-	private final Map<PropertyDescriptor, TypeDescriptor> typeDescriptorCache;
+	private final ConcurrentMap<PropertyDescriptor, TypeDescriptor> typeDescriptorCache;
 
 
 	/**
@@ -295,7 +300,7 @@ private CachedIntrospectionResults(Class<?> beanClass) throws BeansException {
 									"; editor [" + pd.getPropertyEditorClass().getName() + "]" : ""));
 				}
 				pd = buildGenericTypeAwarePropertyDescriptor(beanClass, pd);
-				this.propertyDescriptorCache.putIfAbsent(pd.getName(), pd);
+				this.propertyDescriptorCache.put(pd.getName(), pd);
 			}
 
 			this.typeDescriptorCache = new ConcurrentHashMap<PropertyDescriptor, TypeDescriptor>();
@@ -347,8 +352,9 @@ private PropertyDescriptor buildGenericTypeAwarePropertyDescriptor(Class<?> bean
 		}
 	}
 
-	void addTypeDescriptor(PropertyDescriptor pd, TypeDescriptor td) {
-		this.typeDescriptorCache.putIfAbsent(pd, td);
+	TypeDescriptor addTypeDescriptor(PropertyDescriptor pd, TypeDescriptor td) {
+		TypeDescriptor existing = this.typeDescriptorCache.putIfAbsent(pd, td);
+		return (existing != null ? existing : td);
 	}
 
 	TypeDescriptor getTypeDescriptor(PropertyDescriptor pd) {