Logging in programming, refers to recording activities/events. Usually, the application developers should take care of logging.

To make the job of logging easier, Java provides various frameworks − log4J, java.util.logging (JUL), tiny log, logback, etc.

Logging Framework Overview

A logging framework usually contains three elements −

Logger

Captures the message along with the metadata.

Formatter

Formats the messages captured by the logger.

Handler

The Handler or appender finally dispatches the messages either by printing on the console or, by storing in the database or, by sending through an email.

Some frameworks combine the logger and appender elements to speed up the operations.

Logger Object

To log a message, the application sends a logger object (sometimes along with the exceptions if any) with name and security level.

Severity Level

The messages logged will be of various levels. The following table lists down the general levels of logging.