Java Academy · Lesson

Configuring Logback

Appenders, patterns, and levels.

What Is Logback?

Logback is a popular SLF4J backend, written by the same author as Log4j. It actually performs the logging that SLF4J calls describe.

You configure it with a file named logback.xml on the classpath, usually under src/main/resources.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Main {
    private static final Logger log = LoggerFactory.getLogger(Main.class);
    public static void main(String[] args) {
        log.info("Logback reads logback.xml at startup");
    }
}

Three Building Blocks

Logback config has three core concepts:

Logger: named source of log events, with a level.
Appender: a destination (console, file).
Encoder/Layout: formats the event into text.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Main {
    private static final Logger log = LoggerFactory.getLogger(Main.class);
    public static void main(String[] args) {
        log.info("logger -> appender -> encoder -> output");
    }
}

All lessons in this course

← Back to Java Academy