private static void failTooBig(Object val, Object max, String defName, String valKey) {
        throw new IllegalArgumentException("Value '" + valKey + "' outside range " +
                                           "in definition '" + defName + "': " + val + ">" + max);
    }
Throws if the given value is not legal.
config/src/main/java/com/yahoo/vespa/config/ConfigDefinition.java