checkstyle

name	checkstyle
description	Check and fix Checkstyle violations in jhelm modules
argument-hint	["module"]
allowed-tools	Bash(./mvnw *), Bash(python3 *)

Check and Fix Checkstyle Violations

Configuration

• Plugin: maven-checkstyle-plugin 3.6.0 with spring-javaformat-checkstyle 0.0.43
• Suppressions: checkstyle-suppressions.xml in project root
• Violations fail the build at validate phase (before compile)

Step 1: Check violations

All modules:

./mvnw validate 2>&1 | grep -E "violations|ERROR.*\.java"

Specific module (e.g., /checkstyle jhelm-core):

./mvnw validate -pl $ARGUMENTS 2>&1 | grep "^\[ERROR\]"

Step 2: Auto-format first

Always run spring-javaformat:apply before checking violations — it fixes indentation/spacing automatically:

./mvnw spring-javaformat:apply

Step 3: Fix remaining violations with Python script

Run the persistent fix script:

python3 .claude/scripts/fix_violations.py .

This fixes: SpringCatch (e → ex), NeedBraces, SpringLambda (parens + block collapse), SpringTernary, and AvoidStarImport expansion.

Step 4: Handle special violations manually

Violation	Fix
InnerTypeLast	Move inner classes AFTER all methods
SpringHideUtilityClassConstructor	Add private Constructor() {} AND make class final
FinalClass	Add final to class declaration
NestedIfDepth > 3	Extract helper method or add to checkstyle-suppressions.xml
SpringMethodVisibility (interface impl)	Add suppression to checkstyle-suppressions.xml
AnnotationUseStyle trailing comma	Remove , before }) in @CsvSource etc.

Step 5: Re-format and validate

./mvnw spring-javaformat:apply && ./mvnw validate

Critical Pitfalls

1. Lambda parens vs switch patterns: case Boolean b -> b — do NOT add parens to switch pattern variables. Check if preceded by uppercase type name or case keyword.
2. Lambda parens vs switch default: default -> value — do NOT add parens. default is a Java keyword.
3. Ternary in lambda body: (args) -> condition ? a : b — the -> arrow is a boundary; the condition starts AFTER ->. Do NOT wrap the lambda params in the ternary condition.
4. == vs = in find_condition_start: When scanning backward for ternary condition start, == at position i has line[i-1]='=' — skip it. AND line[i+1]='=' also means it's ==, skip.
5. Star import for removeIf(r ->): r is preceded by ( from the method call, NOT from lambda parens. Check if char AFTER identifier is ) to detect already-parenthesized.
6. Missing imports after star import expansion: Manually check for Base64, BufferedInputStream, VersionInfo, etc. that may not be in the predefined class lists.

Suppressions file (checkstyle-suppressions.xml)

Located at project root. Current suppressions:

• SpringHeader, SpringTestFileName, JavadocPackage — project conventions differ
• RegexpSinglelineJava — JUnit 5 assertions used instead of AssertJ
• SpringImportOrder — handled by spring-javaformat:apply
• RequireThis — not enforced in this project
• All Javadoc* and SpringJavadoc — not required
• SpringMethodVisibility for KpsComparisonTest.java — TrustManager interface requires public
• NestedIfDepth for RepoManager.java — intentional deep YAML parsing