Most detailed information. Should be used very sparingly.
Detailed information on the flow through the system. This log level should never be used in customer-facing environments, but many applications will log debug-level information for troubleshooting purposes
Interesting runtime events (startup/shutdown). Expect these to be immediately visible on a console, so be conservative and keep to a minimum. This log level contains informational details and is typically not going to be acted upon by Operations
Use of deprecated APIs, poor usage of API, 'almost' errors, other runtime situations that are undesirable or unexpected, but not necessarily "wrong". This log level contains details that can be important but is typically not going to be acted upon by Operations. Some WARN level log items may be escalated if thresholds are met
Other runtime errors or unexpected conditions. This log level contains important error details that must be escalated immediately to remediate failure. This should be as actionable and detailed as possible. Business-level information (e.g. “Customer login was incorrect”) should not be logged at this level, but rather at the WARN level with “BUSINESS ALERT” in the message because they are not application failures.
Severe errors that cause premature termination. An extreme version of “ERROR”
List of session parameters that are printed to the INFO severity level of the log record: