Writing effective logs in a Spring Boot application helps you quickly identify issues and understand application behavior. Always create meaningful log messages that clearly describe what is happening in your code. For example, instead of logging a vague message like "Error occurred", use something more descriptive such as "Failed to process order with ID: 1234". This makes troubleshooting much faster when you review logs later.

Be careful to avoid logging sensitive data such as passwords, credit card numbers, or personal user information. Logging this type of information can create security risks if your logs are accessed by unauthorized users. Instead, only include non-sensitive identifiers or general context that helps you understand the problem without exposing private details.

Maintaining consistent formatting in your log messages is important for readability and automated log analysis. Use a clear structure, such as always starting with the action, followed by relevant identifiers or context. For example, "User login failed: username=alice, reason=invalid password". This makes it easier to search and filter logs using tools or scripts.

Following these best practices in your Spring Boot application ensures your logs are useful, secure, and easy to work with as your application grows.