if (logger.isDebugEnabled()) {
                    logger.debug("principal: {}", principal);
                }
            } catch (final Exception e) {
                final String msg = "Failed to process Authorization Header: " + request.getHeader(Constants.AUTHZ_HEADER);
                if (logger.isDebugEnabled()) {
                    logger.debug(msg);
                }

public class CrawlerLogHelper extends LogHelperImpl {
    private static final Logger logger = LogManager.getLogger(CrawlerLogHelper.class);

    @Override
    public void log(final LogType key, final Object... objs) {
        if (!ComponentUtil.available()) {
            if (logger.isDebugEnabled()) {
                logger.debug("container was destroyed.");
            }
            return;
        }

import org.lastaflute.web.validation.exception.ValidationErrorException;

public class AdminPluginAction extends FessAdminAction {

    public static final String ROLE = "admin-plugin";

    private static final Logger logger = LogManager.getLogger(AdminPluginAction.class);

    private static final String UPLOAD = "upload";

    @Override
    protected void setupHtmlData(final ActionRuntime runtime) {
        super.setupHtmlData(runtime);

#log4j.logger.jcifs.smb.SmbTreeConnection: DEBUG
#log4j.logger.jcifs.smb.SmbTransportImpl: DEBUG
#log4j.logger.jcifs.util.transport.Transport: DEBUG
#log4j.logger.jcifs.smb.DfsImpl: DEBUG
#log4j.logger.jcifs.smb: DEBUG
#log4j.logger.jcifs.smb.SmbFileOutputStream: TRACE
#log4j.logger.jcifs.smb.SigningDigest: TRACE

+-----+

* Logger Name

 Logger name is basically the classical fully qualified class name: it's not visible by default, but can be activated (see {{{/maven-logging.html}user documentation}}).

 Notice that before Maven 3.1.0, with logger created by Maven, some code used to pass logger from class to class because it could not create a new logger:

import org.codelibs.fess.crawler.exception.CrawlerSystemException;
import org.dbflute.utflute.core.PlainTestCase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author shinsuke
 *
 */
public class XmlExtractorTest extends PlainTestCase {
    private static final Logger logger = LoggerFactory.getLogger(XmlExtractorTest.class);

    public XmlExtractor xmlExtractor;

    @Override

          if (!buffer.isProbablyUtf8()) {
            logger.log("")
            logger.log("<-- END HTTP (${totalMs}ms, binary ${buffer.size}-byte body omitted)")
            return response
          }

          if (contentLength != 0L) {
            logger.log("")
            logger.log(buffer.clone().readString(charset))
          }

          logger.log(
            buildString {

public class LanguageHelper {
    private static final Logger logger = LogManager.getLogger(LanguageHelper.class);

    protected String[] langFields;

    protected String[] supportedLanguages;

    protected LanguageDetector detector;

    protected int maxTextLength;

    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {
            logger.debug("Initialize {}", this.getClass().getSimpleName());

        public void setupServerConfigIfNeeds(final BootLogger logger, final Tomcat server, final Connector connector,
                final Properties props, final List<String> readConfigList) {
            if (props == null) {
                return;
            }
            super.setupServerConfigIfNeeds(logger, server, connector, props, readConfigList);
            doSetupServerConfig(logger, props, "SSLEnabled", value -> {

        R invokerRequest = context.invokerRequest;
        Logger logger = context.logger;
        if (invokerRequest.options().relaxedChecksums().orElse(false)) {
            logger.info("Disabling strict checksum verification on all artifact downloads.");
        } else if (invokerRequest.options().strictChecksums().orElse(false)) {
            logger.info("Enabling strict checksum verification on all artifact downloads.");
        }