Why is it sometimes useful to implement filters in your logging?

With log filters you can control the log messages that are published. A filter leaves out messages of a certain severity level from a subsystem, such as JDBC or JMS, or according to a specified criteria (for example, only during peak hours). Only the log messages that satisfy the filter criteria are published. You can create separate filters for the messages that each server instance either writes to its server log file, stdout or memory buffer, or broadcasts to the domain-wide message log.

The default built-in filters such as severity levels filter out a lot already, but creating your own ones is really cool!

You can create a log filter by accessing the Log Filters tab in the Domain Home.

When you have created the log filter, you can add an expression you like to filter. We use a simple one: we only want to see the BEA-000360, Server Instance is "RUNNING".

If you have saved your log filter, you will have to apply it. You must select the server instance on which you want to apply the filter. In the drop-down menu, your newly created filter should appear, as shown in the following screenshot: