static String getParam(String prefix, String name) {
        String ret = name.substring(prefix.length());
        ret = ret
                .substring(0, 1)
                .toLowerCase(Locale.ROOT) + ret.substring(1);
        return ret;
    }
@param fieldName     can be null -- used only for logging and debugging
@param obj
@param jsonGenerator
@throws TikaSerializationException
tika-serialization/src/main/java/org/apache/tika/serialization/TikaJsonSerializer.java