Fix race condition in AnntationMethodHER

Issues: SPR-9138

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/mvc/annotation/AnnotationMethodHandlerExceptionResolver.java

@@ -75,8 +75,7 @@ import org.springframework.web.servlet.View;
 public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExceptionResolver {
 
 	// dummy method placeholder
-	private static final Method NO_METHOD_FOUND = ClassUtils
-			.getMethodIfAvailable(System.class, "currentTimeMillis", null);
+	private static final Method NO_METHOD_FOUND = ClassUtils.getMethodIfAvailable(System.class, "currentTimeMillis", (Class<?>[]) null);
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
@@ -134,10 +133,9 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	private Method findBestExceptionHandlerMethod(Object handler, final Exception thrownException) {
 		final Class<?> handlerType = handler.getClass();
 		final Class<? extends Throwable> thrownExceptionType = thrownException.getClass();
-
 		Method handlerMethod = null;
-		Map<Class<? extends Throwable>, Method> handlers = exceptionHandlerCache
-				.get(handlerType);
+
+		Map<Class<? extends Throwable>, Method> handlers = exceptionHandlerCache.get(handlerType);
 
 		if (handlers != null) {
 			handlerMethod = handlers.get(thrownExceptionType);
@@ -173,7 +171,9 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 			}
 		});
 
-		return getBestMatchingMethod(resolverMethods, thrownException);
+		handlerMethod = getBestMatchingMethod(resolverMethods, thrownException);
+		handlers.put(thrownExceptionType, (handlerMethod == null ? NO_METHOD_FOUND : handlerMethod));
+		return handlerMethod;
 	}
 
 	/**
@@ -204,19 +204,19 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	}
 
 	/**
-	 * Returns the best matching method. Uses the {@link DepthComparator}.
+	 * Uses the {@link DepthComparator} to find the best matching method
+	 * @return the best matching method or {@code null}.
 	 */
 	private Method getBestMatchingMethod(
 			Map<Class<? extends Throwable>, Method> resolverMethods, Exception thrownException) {
 
-		if (!resolverMethods.isEmpty()) {
-			Class<? extends Throwable> closestMatch =
-					ExceptionDepthComparator.findClosestMatch(resolverMethods.keySet(), thrownException);
-			return resolverMethods.get(closestMatch);
-		}
-		else {
+		if (resolverMethods.isEmpty()) {
 			return null;
 		}
+		Class<? extends Throwable> closestMatch =
+				ExceptionDepthComparator.findClosestMatch(resolverMethods.keySet(), thrownException);
+		Method method = resolverMethods.get(closestMatch);
+		return ((method == null) || (NO_METHOD_FOUND == method)) ? null : method;
 	}
 
 	/**
@@ -225,13 +225,13 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	private Object[] resolveHandlerArguments(Method handlerMethod, Object handler,
 			NativeWebRequest webRequest, Exception thrownException) throws Exception {
 
-		Class[] paramTypes = handlerMethod.getParameterTypes();
+		Class<?>[] paramTypes = handlerMethod.getParameterTypes();
 		Object[] args = new Object[paramTypes.length];
 		Class<?> handlerType = handler.getClass();
 		for (int i = 0; i < args.length; i++) {
 			MethodParameter methodParam = new MethodParameter(handlerMethod, i);
 			GenericTypeResolver.resolveParameterType(methodParam, handlerType);
-			Class paramType = methodParam.getParameterType();
+			Class<?> paramType = methodParam.getParameterType();
 			Object argValue = resolveCommonArgument(methodParam, webRequest, thrownException);
 			if (argValue != WebArgumentResolver.UNRESOLVED) {
 				args[i] = argValue;
@@ -267,7 +267,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 		}
 
 		// Resolution of standard parameter types...
-		Class paramType = methodParameter.getParameterType();
+		Class<?> paramType = methodParameter.getParameterType();
 		Object value = resolveStandardArgument(paramType, webRequest, thrownException);
 		if (value != WebArgumentResolver.UNRESOLVED && !ClassUtils.isAssignableValue(paramType, value)) {
 			throw new IllegalStateException("Standard argument type [" + paramType.getName() +
@@ -287,7 +287,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	 * @param thrownException the exception thrown
 	 * @return the argument value, or {@link org.springframework.web.bind.support.WebArgumentResolver#UNRESOLVED}
 	 */
-	protected Object resolveStandardArgument(Class parameterType, NativeWebRequest webRequest,
+	protected Object resolveStandardArgument(Class<?> parameterType, NativeWebRequest webRequest,
 			Exception thrownException) throws Exception {
 
 		if (parameterType.isInstance(thrownException)) {

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/AnnotationMethodHandlerExceptionResolver.java

@@ -84,10 +84,10 @@ import org.springframework.web.servlet.support.RequestContextUtils;
 public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExceptionResolver {
 
 	// dummy method placeholder
-	private static final Method NO_METHOD_FOUND = ClassUtils.getMethodIfAvailable(System.class, "currentTimeMillis", null);
-	
-	private final Map<Class<?>, Map<Class<? extends Throwable>, Method>> exceptionHandlerCache = 
-			new ConcurrentHashMap<Class<?>, Map<Class<? extends Throwable>, Method>>(); 
+	private static final Method NO_METHOD_FOUND = ClassUtils.getMethodIfAvailable(System.class, "currentTimeMillis", (Class<?>[]) null);
+
+	private final Map<Class<?>, Map<Class<? extends Throwable>, Method>> exceptionHandlerCache =
+			new ConcurrentHashMap<Class<?>, Map<Class<? extends Throwable>, Method>>();
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
@@ -157,7 +157,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 		final Class<?> handlerType = ClassUtils.getUserClass(handler);
 		final Class<? extends Throwable> thrownExceptionType = thrownException.getClass();
 		Method handlerMethod = null;
-		
+
 		Map<Class<? extends Throwable>, Method> handlers = exceptionHandlerCache.get(handlerType);
 
 		if (handlers != null) {
@@ -170,7 +170,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 			handlers = new ConcurrentHashMap<Class<? extends Throwable>, Method>();
 			exceptionHandlerCache.put(handlerType, handlers);
 		}
-		
+
 		final Map<Class<? extends Throwable>, Method> resolverMethods = handlers;
 
 		ReflectionUtils.doWithMethods(handlerType, new ReflectionUtils.MethodCallback() {
@@ -228,19 +228,19 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	}
 
 	/**
-	 * Returns the best matching method. Uses the {@link DepthComparator}.
+	 * Uses the {@link DepthComparator} to find the best matching method
+	 * @return the best matching method or {@code null}.
 	 */
 	private Method getBestMatchingMethod(
 			Map<Class<? extends Throwable>, Method> resolverMethods, Exception thrownException) {
 
-		if (!resolverMethods.isEmpty()) {
-			Class<? extends Throwable> closestMatch =
-					ExceptionDepthComparator.findClosestMatch(resolverMethods.keySet(), thrownException);
-			return resolverMethods.get(closestMatch);
-		}
-		else {
+		if (resolverMethods.isEmpty()) {
 			return null;
 		}
+		Class<? extends Throwable> closestMatch =
+				ExceptionDepthComparator.findClosestMatch(resolverMethods.keySet(), thrownException);
+		Method method = resolverMethods.get(closestMatch);
+		return ((method == null) || (NO_METHOD_FOUND == method)) ? null : method;
 	}
 
 	/**
@@ -249,13 +249,13 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	private Object[] resolveHandlerArguments(Method handlerMethod, Object handler,
 			NativeWebRequest webRequest, Exception thrownException) throws Exception {
 
-		Class[] paramTypes = handlerMethod.getParameterTypes();
+		Class<?>[] paramTypes = handlerMethod.getParameterTypes();
 		Object[] args = new Object[paramTypes.length];
 		Class<?> handlerType = handler.getClass();
 		for (int i = 0; i < args.length; i++) {
 			MethodParameter methodParam = new MethodParameter(handlerMethod, i);
 			GenericTypeResolver.resolveParameterType(methodParam, handlerType);
-			Class paramType = methodParam.getParameterType();
+			Class<?> paramType = methodParam.getParameterType();
 			Object argValue = resolveCommonArgument(methodParam, webRequest, thrownException);
 			if (argValue != WebArgumentResolver.UNRESOLVED) {
 				args[i] = argValue;
@@ -290,7 +290,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 		}
 
 		// Resolution of standard parameter types...
-		Class paramType = methodParameter.getParameterType();
+		Class<?> paramType = methodParameter.getParameterType();
 		Object value = resolveStandardArgument(paramType, webRequest, thrownException);
 		if (value != WebArgumentResolver.UNRESOLVED && !ClassUtils.isAssignableValue(paramType, value)) {
 			throw new IllegalStateException(
@@ -311,7 +311,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 	 * @param thrownException the exception thrown
 	 * @return the argument value, or {@link WebArgumentResolver#UNRESOLVED}
 	 */
-	protected Object resolveStandardArgument(Class parameterType, NativeWebRequest webRequest,
+	protected Object resolveStandardArgument(Class<?> parameterType, NativeWebRequest webRequest,
 			Exception thrownException) throws Exception {
 
 		if (parameterType.isInstance(thrownException)) {
@@ -395,7 +395,7 @@ public class AnnotationMethodHandlerExceptionResolver extends AbstractHandlerExc
 			return new ModelAndView().addAllObjects(((Model) returnValue).asMap());
 		}
 		else if (returnValue instanceof Map) {
-			return new ModelAndView().addAllObjects((Map) returnValue);
+			return new ModelAndView().addAllObjects((Map<String, Object>) returnValue);
 		}
 		else if (returnValue instanceof View) {
 			return new ModelAndView((View) returnValue);