What line should be edited in log4j.properties to ensure only WARN level logs and above are displayed in the console?

To ensure that only WARN level logs and above are displayed in the console, the correct line to edit in the log4j.properties file is setting the root category to WARN. By doing this, you define the logging level threshold for your application.

When the logging level is set to WARN, it means that logs at the WARN level and any higher severity levels (like ERROR and FATAL) will be processed and displayed, while lower severity logs (such as INFO and DEBUG) will be ignored. This adjustment allows for a more focused log output, minimizing noise from less significant messages and enabling developers or administrators to concentrate on important warnings and error messages that might require attention.

This setup is particularly useful in production environments where excessive logging can lead to performance issues or cluttered logs, making it harder to identify critical issues. The other options would allow lower levels of logs to be displayed, which is not aligned with the requirement of showing only WARN level logs and above.