Groovy Coding Practices

Groovy Coding Practices

Application skill for Groovy style learning (from the archived awesome-guidelines style capsules). For Grails-specific conventions, combine with stack capsules in skills/*-foundation and project CodeNarc rulesets.

Core Principle

Groovy quality is idiomatic expressiveness with typed public seams, GDK and property syntax internally, explicit types on shared API.

When to Use / NOT

• Groovy scripts, Gradle plugins, Grails apps, JVM automation libraries.
• Setting up CodeNarc, npm-groovy-lint, Spock tests in CI.

NOT when:

• Pure Java/Kotlin modules, use language-specific practice skills.
• Generated AST/transform output, validate generators.

Workflow

1. Syntax, semicolons, def, parens, strings (groovy-style-syntax-idioms.md).
2. Objects, POGOs, with/tap, equality (groovy-style-objects-properties.md).
3. Collections, GDK, truth, nav (groovy-style-collections-gdk.md).
4. API, public typing, assert (groovy-style-typing-api.md).
5. Verify, CodeNarc/npm-groovy-lint, compile, tests on changed sources.

Red Flags

• Semicolons on every line
• def String / def constructors
• Redundant public everywhere
• each() { } with empty parens
• Manual getter/setter boilerplate on POGOs
• String + where GString fits
• Nested null checks vs ?.
• == for reference identity
• Untyped public def methods
• Accidental return from assignment in def methods
• Java .class literals where unnecessary
• Obsolete Vector/Hashtable
• Blanket catch (any) without justification

Verification

• CodeNarc / npm-groovy-lint (project ruleset)
• ./gradlew compileGroovy or project build
• Spock/JUnit tests on changed modules
• Capsule checklist on public method signatures

References

• awesome-guidelines/references/groovy-style-learning-note.md
• awesome-guidelines/references/groovy-style-syntax-idioms.md
• awesome-guidelines/references/groovy-style-objects-properties.md
• awesome-guidelines/references/groovy-style-collections-gdk.md
• awesome-guidelines/references/groovy-style-typing-api.md