#fixed code
                                static Object invokeSingle(final Object proxy,
                               final Method method,
                               final Envelop envelop) {
        final Class<?> argType = method.getParameterTypes()[Values.IDX];
        // Append single argument
        final Object analyzed = TypedArgument.analyze(envelop, argType);
        if (Objects.isNull(analyzed)) {
            // One type dynamic here
            final Object reference = Objects.nonNull(envelop) ? envelop.data() : new JsonObject();
            // Non Direct
            Object parameters = reference;
            if (JsonObject.class == reference.getClass()) {
                final JsonObject json = (JsonObject) reference;
                if (isInterface(json)) {
                    // Proxy mode
                    if (Values.ONE == json.fieldNames().size()) {
                        // New Mode for direct type
                        parameters = json.getValue("0");
                    }
                }
            }
            final Object arguments = ZeroSerializer.getValue(argType, Ut.toString(parameters));
            return Ut.invoke(proxy, method.getName(), arguments);
        } else {
            /*
             * XHeader
             * User
             * Session
             * These three argument types could be single
             */
            return Ut.invoke(proxy, method.getName(), analyzed);
        }
    }
#vulnerable code 
                                static Object invokeSingle(final Object proxy,
                               final Method method,
                               final Envelop envelop) {
        final Class<?> argType = method.getParameterTypes()[Values.IDX];
        // One type dynamic here
        final Object reference = Objects.nonNull(envelop) ? envelop.data() : new JsonObject();
        // Non Direct
        Object parameters = reference;
        if (JsonObject.class == reference.getClass()) {
            final JsonObject json = (JsonObject) reference;
            if (isInterface(json)) {
                // Proxy mode
                if (Values.ONE == json.fieldNames().size()) {
                    // New Mode for direct type
                    parameters = json.getValue("0");
                }
            }
        }
        final Object arguments = ZeroSerializer.getValue(argType, Ut.toString(parameters));
        return Ut.invoke(proxy, method.getName(), arguments);
    } 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE