Understanding how to configure log levels is essential for managing application behavior in Spring Boot. Log levels help you control the amount and type of information written to your logs, making it easier to troubleshoot issues and monitor your application's health.

Log levels

Log levels help you control how much detail appears in your application logs. Each log message has a level that shows its importance. Common log levels are TRACE, DEBUG, INFO, WARN, and ERROR.

In Spring Boot, you can set log levels in the application.properties or application.yml file. To set the level for your whole application, add a line like:

logging.level.root=INFO

You can also set log levels for specific packages or classes:

logging.level.com.example.myapp=DEBUG

Choose log levels based on the type of information:

• Use TRACE for very detailed messages, often for diagnosing problems;
• Use DEBUG for general debugging information during development;
• Use INFO for routine application events, such as startup or shutdown messages;
• Use WARN for events that are unusual or might cause problems, but do not stop the application;
• Use ERROR for serious issues that prevent parts of the application from working.

Setting the right log level helps you find issues quickly without overloading your logs with too much data.