Use logging frameworks to record application events for debugging and monitoring.
While `System.out.println()` is useful for quick debugging during development, it is a poor choice for logging in a real application. It offers no control over the output, cannot be easily disabled, and mixes application output with diagnostic information. A far better approach is to use a dedicated logging framework. Logging is the practice of recording application events, errors, and other important information to a persistent medium, such as a file or a database. This information is invaluable for debugging problems, monitoring the application's health, and auditing its activity. Java has several popular logging frameworks, such as Log4j, Logback, and the built-in `java.util.logging` package. A common practice is to use a logging facade like SLF4J (Simple Logging Facade for Java), which provides a common API that can be used with different underlying logging implementations. This decouples your application code from any specific logging framework. Logging frameworks introduce the concept of log levels, such as `TRACE`, `DEBUG`, `INFO`, `WARN`, and `ERROR`. You can configure the application to only record messages at or above a certain severity level. For example, in a production environment, you might only log `INFO` and higher, while in a development environment, you might enable `DEBUG` to get more detailed information. This configuration can be changed without modifying the application code, making logging a powerful and flexible tool for any serious Java developer.