Author: Steve Young
Keywords: JMRI help display view edit update debug log logging category categories log4j log4j2 slf4j

# JMRI: Display / Edit Log Categories

This tool can be opened via Debug ⇒ Display / Edit Log Categories

This screen displays a list of the current Logging Categories in use by JMRI.

Clicking the Refresh Categories button updates the main category list (and the category selection box under the category list).

An entry such as

`apps.jmrit.log.Log4JTreePane { INFO }`

means that any logging statements produced by Log4JTreePane of INFO, or the higher levels WARN and ERROR level will be logged.

The Logging levels are :

- TRACE ( + DEBUG + INFO + WARN + ERROR )
- DEBUG ( + INFO + WARN + ERROR )
- INFO ( + WARN + ERROR )
- WARN ( + ERROR )
- ERROR
- OFF

Levels within [ ] brackets have been set within the Logging configuration.
Levels within { } braces indicate that the Level has been inherited.

`apps.jmrit.log.Log4JTreePane { INFO }`

Indicates that the INFO Level is inherited from one of these categories :

- apps.jmrit.log
- apps.jmrit
- apps
- Root Logging Level

Categories can be created by entering a new name in the Category selection box and then editing the Logging Level.

It can sometimes be useful to change the Level for a Category.

At the bottom of the screen, select the category, the new level and click Set new Logging Level for this session.

Changes made to Logging reporting levels using this screen will last for the remainder of the JMRI session.
Changes affect all logs, i.e., the live console log and logging to Files.

The TRACE debug level may produce a LOT of output, expect system freezes if this is set for the Default Logging Level.

To make permanent changes to the logging levels, see JMRI Debugging and Logging which discusses the Logging Configuration File, (default_lcf.xml) options.