Documentation & Logging Rules

About

Documentation & Logging Rules define guidelines for writing clear code documentation and using logging effectively in a Spring project. Proper documentation ensures that code is understandable and maintainable, while structured logging enables troubleshooting, auditing, and monitoring.

These rules cover:

• Javadoc conventions for classes, methods, and fields.

• Inline comments for complex logic.

• Logging practices using Spring-supported frameworks like SLF4J / Logback / Log4j2.

• Guidelines for log levels, messages, and context enrichment.

Purpose

The purpose of Documentation & Logging Rules is to ensure that the Spring application code is readable, maintainable, and observable during runtime.

Key objectives include:

1. Improve code readability and maintainability

   • Clear documentation helps developers understand class responsibilities, method behavior, and complex logic.

2. Support troubleshooting and monitoring

   • Consistent logging provides actionable insights for debugging, error tracking, and performance monitoring.

3. Enforce standardized logging practices

   • Ensures log levels (DEBUG, INFO, WARN, ERROR) are used appropriately, and log messages are meaningful and structured.

4. Enable compliance and auditing

   • Proper logging practices support audit trails for security and business-critical operations.

5. Facilitate team collaboration

   • Standardized documentation and logging conventions make it easier for new team members to understand and maintain code.

Rules

1. Class and Interface Documentation

• All public classes and interfaces should have Javadoc comments describing:

  • Purpose of the class/interface.

  • Responsibilities and behaviour.

  • Key interactions with other components.

• Example structure:

  /**
   * Service class responsible for managing Employee entities.
   * Handles CRUD operations and business validation.
   */
  public class EmployeeService { ... }

2. Method Documentation

• Public and protected methods should include Javadoc specifying:

  • Purpose of the method.

  • Input parameters (@param).

  • Return type (@return).

  • Exceptions thrown (@throws).

• Inline comments can be used sparingly for complex logic or calculations.

3. Logging Practices

• Use SLF4J (LoggerFactory) for logging instead of System.out.println.

• Log messages should be clear, descriptive, and contextual.

  • Include identifiers like IDs, user information, or transaction context where applicable.

• Use appropriate log levels:

  • DEBUG – Detailed technical information for developers.

  • INFO – High-level events (e.g., user login, transaction processed).

  • WARN – Recoverable issues or unexpected behavior.

  • ERROR – Exceptions or failures requiring investigation.

4. Exception Logging

• Exceptions should be logged with stack trace and meaningful messages.

• Avoid logging sensitive data (passwords, tokens, PII).

• Example:

  log.error("Failed to process employee with ID {}: {}", employeeId, e.getMessage(), e);

5. Audit and Business Logging

• Log important business events (e.g., approvals, payments, critical updates) using a dedicated audit logger or structured logging format.

6. Consistency

• Use consistent log message format across the application.

• Follow standard terminology and casing for log messages (e.g., “User created successfully” not “user CREATED”).

7. Documentation Updates

• Update class/method documentation whenever the behavior, parameters, or outputs change.

• Ensure deprecated methods/classes are documented with @deprecated tags.