Logger logger = Logger.getLogger(MyClass.class); if (logger.isDebugEnabled()) { // Perform expensive operation needed to generate debug message Object debugData = generateDebugData(); logger.debug("Debug message with data: " + debugData); }This example ensures that the expensive operation is only performed if debug messages are actually going to be logged, which can help to improve performance. Overall, the org.apache.log4j package library provides powerful logging capabilities for Java applications, allowing developers to easily configure and manage different logging levels and message types.