Spring Исключение MVC. Вызов метода запроса привел к исключению: public static native long long java.lang.System.currentTimeMillis()

Ответ 1

Они используют System.currentTimeMillis() как фиктивное значение в кеше методов обработчика исключений:

// dummy method placeholder
private static final Method NO_METHOD_FOUND = ClassUtils.getMethodIfAvailable(System.class, "currentTimeMillis", null);

И он протекает без проверки в конфликте (если вставлен другим потоком между (1) и (2)). Или, возможно, даже без конкуренции из-за разницы между thrownExceptionType и closestMatch:

private Method findBestExceptionHandlerMethod(Object handler, final Exception thrownException) {
    ...
    Map<Class<? extends Throwable>, Method> handlers = exceptionHandlerCache.get(handlerType);

    if (handlers != null) {
        handlerMethod = handlers.get(thrownExceptionType); // 1
        if (handlerMethod != null) {
            return (handlerMethod == NO_METHOD_FOUND ? null : handlerMethod);
        }
    }
    ...
    final Map<Class<? extends Throwable>, Method> resolverMethods = handlers;   
    ...
    handlerMethod = getBestMatchingMethod(resolverMethods, thrownException); // 2
    handlers.put(thrownExceptionType, (handlerMethod == null ? NO_METHOD_FOUND : handlerMethod));
    return handlerMethod;
}

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 {
        return null;
    }
}

См. AnnotationMethodHandlerExceptionResolver.java.

Ответ 2

** Обновление: это было исправлено в Spring 3.1.2 **

Я считаю, что это действительно вызвано состоянием гонки. Я создал для него проблему Jira, где я попытался объяснить, что происходит: https://jira.springsource.org/browse/SPR-9138

Вот выдержка из объяснения из проблемы jira:

private Method findBestExceptionHandlerMethod(Object handler, final Exception thrownException) {
    //T1 and T2 enters method
    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);
    //Timing makes (handlers==null) for T1 (handler != null) for T2
    if (handlers != null) {
        handlerMethod = handlers.get(thrownExceptionType);
        //handlerMethod is still null for T2
        if (handlerMethod != null) {
            return (handlerMethod == NO_METHOD_FOUND ? null : handlerMethod);
        }
    }
    else {
        //T1 does this, the hashmap created here is read by T2 in if-test above matching this else block
        handlers = new ConcurrentHashMap<Class<? extends Throwable>, Method>();
        exceptionHandlerCache.put(handlerType, handlers);
    }

    //handlers is empty for both T1 and T2, the two threads' resolverMethod variables will reference the same
    // ConcurrentHashMap instance
    final Map<Class<? extends Throwable>, Method> resolverMethods = handlers;

    //This block does not find a match for the exception
    ReflectionUtils.doWithMethods(handlerType, new ReflectionUtils.MethodCallback() {
        public void doWith(Method method) {
            method = ClassUtils.getMostSpecificMethod(method, handlerType);
            List<Class<? extends Throwable>> handledExceptions = getHandledExceptions(method);
            for (Class<? extends Throwable> handledException : handledExceptions) {
                if (handledException.isAssignableFrom(thrownExceptionType)) {
                    if (!resolverMethods.containsKey(handledException)) {
                        resolverMethods.put(handledException, method);
                    } else {
                        Method oldMappedMethod = resolverMethods.get(handledException);
                        if (!oldMappedMethod.equals(method)) {
                            throw new IllegalStateException(
                                    "Ambiguous exception handler mapped for " + handledException + "]: {" +
                                            oldMappedMethod + ", " + method + "}.");
                        }
                    }
                }
            }
        }
    });
    //T1 finds no match and puts NO_METHOD_FOUND in cache and returns null
    // When T2 hits this line resolverMethods for T2 reference the same Map that T1 just put the NO_METHOD_FOUND
    // as a result getBestMatchingMethod will return NO_SUCH_METHOD_FOUND (System.timeMillis()) which will be invoked
    // by the doResolveException further up the callstack.
    handlerMethod = getBestMatchingMethod(resolverMethods, thrownException);
    handlers.put(thrownExceptionType, (handlerMethod == null ? NO_METHOD_FOUND : handlerMethod));
    return handlerMethod;
}