change log level at runtime (logback and slf4j)

ChangeLogLevel.java

import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.LoggerContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;

/**
 * change log level at runtime
 * Created by nkcoder on 10/8/16.
 */
public class ChangeLogLevel {
    private static Logger logger = LoggerFactory.getLogger(ChangeLogLevel.class);
    private static String cachedLevel = "";

    public static void main(String[] args) {
        if (args == null || args.length != 1) {
            logger.error("params error.");
            return;
        }
        String logLevel = args[0];

        Level level = Level.toLevel(logLevel.toUpperCase());  // default to Level.DEBUG
        if (cachedLevel.equalsIgnoreCase(level.levelStr)) {
            logger.debug("level: {} not changed", cachedLevel);
            return;
        }
        logger.info("level will change from: {} to: {}", cachedLevel, level.levelStr);
        cachedLevel = level.levelStr;
        LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
        List<ch.qos.logback.classic.Logger> loggerList = loggerContext.getLoggerList();
        loggerList.stream().forEach(tmpLogger -> tmpLogger.setLevel(level));

        logger.debug("debug message");
        logger.info("info message");
        logger.error("error message");
    }
}