# Code Style

> Code style rules for IntelliJ codebase. Use when writing or reviewing code for style compliance.

- Skill: `jetbrains/code-style` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jetbrains/code-style`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jetbrains/code-style/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jetbrains (https://skillmd.com/u/jetbrains)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jetbrains/code-style

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# Code Style

Follow the IntelliJ Coding Guidelines with these IntelliJ-specific rules.

## Language

- **ALWAYS use Kotlin for new files** - Only use Java when modifying existing Java code
- Use idiomatic Kotlin: extension functions, data classes, null safety
- Mark experimental APIs with `@ApiStatus.Experimental`
- **Build scripts Kotlin style**: Follow `community/platform/build-scripts/kotlin-style-recommendations.md` for build-scripts code:
  - Use `@JvmField` for internal data class fields
  - Use `.put()`/`.get()` instead of `[]` operator
  - Use explicit `HashMap`/`HashSet`/`LinkedHashMap` instead of `mutableMapOf()`/`mutableSetOf()`

## Formatting

- Indentation: 2 spaces (4 for Go files)
- Line length: 140 characters max
- Braces: else/catch/finally on new lines
- Only in `/rustrover` directory you must always use standard Kotlin formatting rules with 4 spaces indentation.