# Google Nomulus Nomulus > AST-Aware Java Refactoring - Skill: `tomevault-io/google-nomulus-nomulus` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/google-nomulus-nomulus` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/google-nomulus-nomulus/raw - Safety review: pending (external: skill-scanner PASS, skillspector WARNING) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/google-nomulus-nomulus --- # AST-Aware Java Refactoring This skill uses OpenRewrite to perform Abstract Syntax Tree (AST) based refactoring on Java codebases. This is highly preferred over text-based regex or python scripts because it understands Java semantics, correctly updates imports, and preserves formatting. ## Parameter and Field Renaming (Last Resort) Because OpenRewrite's YAML recipes do not natively support simple variable or field renaming, a custom script is provided: ```bash python3 .gemini/skills/java-ast-refactoring/scripts/safe_rename.py ``` **CRITICAL:** Running this python script is a LAST RESORT. It is a regex-based token replacement that ignores strings and comments, but it lacks true AST understanding. ALWAYS prefer using OpenRewrite recipes (`rewrite.yml`) for structural changes like renaming classes, methods, or moving targets, as OpenRewrite correctly handles imports, types, and cross-file references safely. ## Usage 1. Create a `rewrite.yml` recipe file in the workspace root. Refer to `.gemini/skills/java-ast-refactoring/references/rewrite_recipes.md` for syntax. 2. Execute the script: ```bash ./.gemini/skills/java-ast-refactoring/scripts/run_rewrite.sh rewrite.yml ``` 3. The script will safely apply the AST transformations and then automatically run `./gradlew spotlessApply` and `./gradlew javaIncrementalFormatApply` on the modified files to automatically fix any Checkstyle line-length and import ordering issues caused by longer/shorter identifiers. Verify the output using `git diff`. 4. **MANDATORY:** Always run `./gradlew build -x test` (or the equivalent compile task) after running OpenRewrite to ensure no compilation errors were introduced. ## Known Limitations & Troubleshooting * **Static Imports Dropped on Class Rename:** When using `ChangeType` to rename a class, OpenRewrite may sometimes drop static imports for fields/constants belonging to the old class instead of updating them to the new class. If compilation fails due to "cannot find symbol" for a constant after a class rename, manually restore the static import (e.g., `import static com.new.ClassName.CONSTANT;`). * **Continuous Improvement:** If any new issues or edge cases are found while running the refactoring (e.g., build failures, formatting issues, or missed transformations), you **MUST** proactively ask the user if you should permanently update this skill file (`SKILL.md`) and its accompanying scripts (`scripts/run_rewrite.sh`, `scripts/safe_rename.py`) to fix the issue for future use. Do not wait for the user to prompt you to fix the infrastructure. --- > Source: [google/nomulus](https://github.com/google/nomulus) — distributed by [TomeVault](https://tomevault.io).