Appenders: Console, File, Rolling File, Database, and Network Destinations
Learn where logs can go and how appenders connect log events to useful output destinations.
Inside this chapter
- What an Appender Does
- Console and File Appenders
- Rolling File Appenders
- Destination Design Is a Production Decision
Series navigation
Study the chapters in order for the clearest path from beginner logging concepts to advanced operational logging design. Use the navigation at the bottom of each page to move through the full series.
What an Appender Does
An appender is the part of the framework that sends log events somewhere useful. That destination might be the console, a file, a rolling file set, a socket, a centralized collector, or another output target.
Console and File Appenders
Console appenders are common during development and containerized environments. File appenders are often used where logs need to persist locally or be collected by external tooling.
<File name="FileLogger" fileName="logs/app.log">
<PatternLayout pattern="%d %-5level %logger - %msg%n"/>
</File>Rolling File Appenders
Rolling appenders create new log files based on size, time, or both. This prevents one log file from growing forever and makes retention more manageable in production systems.
Destination Design Is a Production Decision
Choosing appenders is not only technical. It affects disk usage, observability workflow, incident response, and how logs move into centralized systems. Advanced teams treat this as part of architecture, not just configuration decoration.