final String defaultLang = ComponentUtil.getFessConfig().getCrawlerDocumentHtmlDefaultLang();
        if (StringUtil.isNotBlank(defaultLang)) {
            return defaultLang;
        }

        return normalizeLang(value);
    }

    public String normalizeLang(final String value) {
        if (StringUtil.isBlank(value)) {
            return null;
        }

import java.util.Map;
import java.util.stream.Collectors;

import javax.annotation.Resource;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.core.stream.StreamUtil;
import org.codelibs.curl.CurlResponse;
import org.codelibs.fess.Constants;
import org.codelibs.fess.annotation.Secured;
import org.codelibs.fess.app.service.ScheduledJobService;