| name | 180-java-observability-logging |
| description | Use when you need to implement or improve Java logging and observability — including selecting SLF4J with Logback/Log4j2, applying proper log levels (ERROR, WARN, INFO, DEBUG, TRACE), parameterized logging, secure logging without sensitive data exposure, environment-specific configuration, log aggregation and monitoring, or validating logging through tests. Part of the skills-for-java project |
| license | Apache-2.0 |
| metadata | {"author":"Juan Antonio Breña Moral","version":"0.13.0-SNAPSHOT"} |
Java Logging Best Practices
Implement effective Java logging following standardized frameworks, meaningful log levels, core practices (parameterized logging, exception handling, no sensitive data), flexible configuration, security-conscious logging, monitoring and alerting, and comprehensive logging validation through testing.
What is covered in this Skill?
- Standardized framework selection: SLF4J facade with Logback or Log4j2
- Meaningful and consistent log levels: ERROR, WARN, INFO, DEBUG, TRACE
- Core practices: parameterized logging, proper exception handling, avoiding sensitive data
- Configuration: environment-specific (logback.xml, log4j2.xml), output formats, log rotation
- Security: mask sensitive data, control log access, secure transmission, GDPR/HIPAA compliance
- Log monitoring and alerting: centralized aggregation (ELK, Splunk, Loki), automated alerts
- Logging validation through testing: assert log messages, verify formats, test levels, measure performance impact
Scope: The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.
Constraints
Before applying any logging recommendations, ensure the project compiles. Compilation failure is a blocking condition. After applying improvements, run full verification.
- MANDATORY: Run
./mvnw compile or mvn compile before applying any change
- SAFETY: If compilation fails, stop immediately — do not proceed until resolved
- VERIFY: Run
./mvnw clean verify or mvn clean verify after applying improvements
- BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each logging pattern
When to use this skill
- Review Java code for logging and observability
- Apply best practices for logging and observability in Java code
Reference
For detailed guidance, examples, and constraints, see references/180-java-observability-logging.md.
