coding-style

name: coding-style description: > Quarkus code style conventions: formatting, visibility, naming, logging, and general style rules for the Quarkus codebase.

Coding Style

Formatting

• Quarkus uses 4-space indentation (no tabs)
• The project enforces formatting via formatter-maven-plugin and impsort-maven-plugin, let the formatting plugins do their work, never use -Dno-format
• Formatter config: independent-projects/ide-config/src/main/resources/eclipse-format.xml
• Run ./mvnw process-sources on your module to auto-format before committing
• The build will fail on formatting violations
• Imports are sorted and organized automatically; do not manually organize imports

Visibility

• Prefer package-private (default) visibility for internal implementation classes
• Use public for user-facing API and for classes/methods that need to be accessed across packages (e.g., processors, recorders, build items). Prefer package-private for purely internal implementation details
• Use protected when designing for extension/subclassing
• Internal classes should go in .internal or .impl sub-packages (e.g., io.quarkus.<ext>.runtime.internal)

Naming

• Deployment processors: <Feature>Processor.java
• Recorders: <Feature>Recorder.java
• Build items: <Description>BuildItem.java
• Config interfaces: <Feature>Config.java or <Feature>BuildTimeConfig.java / <Feature>RuntimeConfig.java
• Artifact IDs: quarkus-<name> (runtime), quarkus-<name>-deployment (deployment)
• Package root: io.quarkus.<extension-name> (hyphens become underscores)

General Style

• No @author tags in Javadoc — Git history tracks authorship
• No wildcard imports
• Never use fully-qualified class names inline — always add an import statement instead
• Avoid static imports except for well-known patterns (e.g., test assertions)
• Minimize lambdas and streams in runtime code — reduces memory footprint for native
• Prefer descriptive method and variable names over comments
• Update existing code comments if your changes make them invalid
• Never remove existing code comments that are still valid
• Keep methods focused and short; extract when complexity warrants it
• Use Optional for API return types that may be absent. In internal hot runtime code paths, direct null checks are acceptable for performance
• Commits should be atomic and semantic — properly squash before submitting PRs. This helps during bisects and makes it easier to revert changes when needed
• Don't use deprecated methods or classes in new code

Logging

• Use JBoss Logging (org.jboss.logging.Logger) as the logging API
• Do NOT use System.out.println or System.err.println
• Do NOT use SLF4J, java.util.logging, or Log4j directly in Quarkus core/extension code

Extension Descriptions

Extension descriptions (in runtime/pom.xml or quarkus-extension.yaml) should:

• Be short (no hover required)
• Describe the function, not the technology
• Start with an action verb, unconjugated (Connect foo, not Connects foo)
• Not mention "Quarkus" or "extension"
• Not repeat the extension name