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Agent skill

141 Java Refactoring With Modern Features

by jabrena in jabrena/plinth

A skill your agent uses when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API…

Apache-2.0Auto-check passedDevelopment

Install 141 Java Refactoring With Modern Features

skills CLI
$ npx skills add jabrena/plinth --skill 141-java-refactoring-with-modern-features -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install jabrena/plinth 141-java-refactoring-with-modern-features --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/jabrena/plinth.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/141-java-refactoring-with-modern-features .claude/skills/141-java-refactoring-with-modern-features && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
141-java-refactoring-with-modern-features
GitHub stars
446
Token cost
~928 tokens
SKILL.md length
345 words
Files
2 (incl. references)
Skills in repo
124
Repo updated
First seen
Licence
Apache-2.0

At a glance

A skill your agent uses when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API…

  • You need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas
  • SKILL.md covers Constraints, When to use this skill, Workflow and Reference
  • Calls mvn
  • Replacing Iterator loops with Stream API

What it does

141 Java Refactoring With Modern Features is an agent skill from jabrena/plinth. Use when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API, adopting Optional for null safety, switching from legacy Date/Calendar to java.time, using collection factory methods, applying text blocks, var inference, or leveraging Java 25 features like flexible constructor bodies and module import declarations. This should trigger for requests such as Review Java code for modern Java development; Apply…

Its SKILL.md is about 930 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/141-java-refactoring-with-modern-features.md`).

It sits in Development, covering Refactoring. It works with Java. The repository describes itself as: Plinth is an AI-native engineering toolkit for modern Java enterprise SDLC, built around reusable Commands, Agents, Skills, and MCP Servers. The licence is Apache-2.0.

When your agent uses it

  • You need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas
  • Replacing Iterator loops with Stream API
  • Adopting Optional for null safety
  • Switching from legacy Date/Calendar to java.time

Example prompts

  • “/141-java-refactoring-with-modern-features”

What it can do on your machine

Read from SKILL.md and the folder at commit dca88dc. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • mvn

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

141 Java Refactoring With Modern Features loads about 928 tokens when it runs, and up to ~14k if it reads all its reference files. Until then it costs about 201 tokens; SKILL.md has 345 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~201
When it runs · the whole SKILL.md, loaded when a task matches
~928
With references · SKILL.md plus every file in references/, read only if the agent opens them
~14k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jabrena/plinth at commit dca88dc, republished under its Apache-2.0 licence (© jabrena). 345 words, ~928 tokens.

Download SKILL.mdSave it as .claude/skills/141-java-refactoring-with-modern-features/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
141-java-refactoring-with-modern-features
description
Use when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API, adopting Optional for null safety, switching from legacy Date/Calendar to java.time, using collection factory methods, applying text blocks, var inference, or leveraging Java 25 features like flexible constructor bodies and module import declarations. This should trigger for requests such as Review Java code for modern Java development; Apply best practices for modern Java development in Java code; Modernize Java code with records pattern matching or switch expressions; Replace legacy idioms with modern Java features; Adopt Java 8+ language features safely. Part of Plinth Toolkit
license
Apache-2.0
metadata.author
Juan Antonio Breña Moral
metadata.version
0.19.0

Modern Java Development Guidelines (Java 8+)

Identify and apply modern Java (Java 8+) refactoring opportunities to improve readability, maintainability, and performance.

What is covered in this Skill?

  • Lambda expressions and method references (over anonymous classes)
  • Stream API for declarative collection processing
  • Optional for null-safe APIs
  • java.time API (replacing Date/Calendar)
  • Default interface methods, var type inference
  • Unmodifiable collection factory methods (List.of(), Set.of(), Map.of())
  • Text blocks for multi-line strings
  • Java 25 Flexible Constructor Bodies (JEP 513)
  • Java 25 Module Import Declarations (JEP 511)

Scope: The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.

Constraints

Before applying any modern Java refactoring, ensure the project compiles. If compilation fails, stop immediately — do not proceed until the project compiles successfully. After applying improvements, run full verification.

  • MANDATORY: Run ./mvnw compile or mvn compile before applying any changes
  • SAFETY: If compilation fails, stop immediately — do not proceed until the project compiles successfully
  • VERIFY: Run ./mvnw clean verify or mvn clean verify after applying improvements
  • BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each modern Java feature
  • EDGE CASE: If request scope is ambiguous, stop and ask a clarifying question before applying changes
  • EDGE CASE: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance

When to use this skill

  • Review Java code for modern Java development
  • Apply best practices for modern Java development in Java code
  • Modernize Java code with records pattern matching or switch expressions
  • Replace legacy idioms with modern Java features
  • Adopt Java 8+ language features safely

Workflow

  1. Compile project before modernization

Run ./mvnw compile or mvn compile and stop immediately if compilation fails.

  1. Read modern-Java reference and identify candidates

Read references/141-java-refactoring-with-modern-features.md and identify high-value opportunities to adopt modern Java features.

  1. Apply modern Java refactorings

Refactor incrementally using appropriate language/library features while preserving behavior and readability.

  1. Verify with full build

Run ./mvnw clean verify or mvn clean verify after applying improvements.

Reference

For detailed guidance, examples, and constraints, see references/141-java-refactoring-with-modern-features.md.

© jabrena, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/141-java-refactoring-with-modern-features of jabrena/plinth.

  • SKILL.md
  • references/141-java-refactoring-with-modern-features.md

Open the folder on GitHubat commit dca88dc

Compare with similar skills

141 Java Refactoring With Modern Features next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

141 Java Refactoring With Modern Features compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
141 Java Refactoring With Modern Features this skilljabrena/plinth446—~928Automated safety check: PassApache-2.0
Java Design Patterns Referencedecebals/claude-code-java7511 repos~4.4kAutomated safety check: PassMIT
Bootui Java Developmentjdubois/boot-ui307—~1.3kAutomated safety check: PassApache-2.0
Goinference-gateway/inference-gateway214—~2.4kAutomated safety check: PassApache-2.0
Java 21 Developer Guide for Grailsapache/grails-core2.9k—~1.9kAutomated safety check: PassApache-2.0
Spring Data Developmentarangodb/spring-data116—~620Automated safety check: PassApache-2.0

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Works with

Categories

Questions about 141 Java Refactoring With Modern Features

What does 141 Java Refactoring With Modern Features do?

A skill your agent uses when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API…. 141 Java Refactoring With Modern Features is an agent skill from jabrena/plinth.time, using collection factory methods, applying text blocks, var inference, or leveraging Java 25 features like flexible constructor bodies and module import declarations.

When should I use 141 Java Refactoring With Modern Features?

141 Java Refactoring With Modern Features fits situations like: you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas; replacing Iterator loops with Stream API; adopting Optional for null safety; switching from legacy Date/Calendar to java.time.

How do I install 141 Java Refactoring With Modern Features in Claude Code?

Run `npx skills add jabrena/plinth --skill 141-java-refactoring-with-modern-features -a claude-code`. Or copy the skill folder (skills/141-java-refactoring-with-modern-features in jabrena/plinth) into .claude/skills/141-java-refactoring-with-modern-features in your project. Claude Code loads it when a task matches its description.

How do I install 141 Java Refactoring With Modern Features in Codex?

Run `npx skills add jabrena/plinth --skill 141-java-refactoring-with-modern-features -a codex`. Or copy the skill folder (skills/141-java-refactoring-with-modern-features in jabrena/plinth) into .agents/skills/141-java-refactoring-with-modern-features in your project. Codex loads it when a task matches its description.

Can I use 141 Java Refactoring With Modern Features in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add jabrena/plinth --skill 141-java-refactoring-with-modern-features -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/141-java-refactoring-with-modern-features, .gemini/skills/141-java-refactoring-with-modern-features, .github/skills/141-java-refactoring-with-modern-features and .opencode/skills/141-java-refactoring-with-modern-features in your project.

What does 141 Java Refactoring With Modern Features need to run?

Going by SKILL.md and its folder, 141 Java Refactoring With Modern Features needs the command-line tools its instructions call (mvn).

Does 141 Java Refactoring With Modern Features access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is 141 Java Refactoring With Modern Features safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does 141 Java Refactoring With Modern Features use?

141 Java Refactoring With Modern Features is published under the Apache-2.0 licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does 141 Java Refactoring With Modern Features use?

About 928 tokens (SKILL.md is roughly 3.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 13k tokens, read only when the agent opens those files.

What are the alternatives to 141 Java Refactoring With Modern Features?

Skills that share tags, products or a category with 141 Java Refactoring With Modern Features: Java Design Patterns Reference (decebals/claude-code-java, 751 stars), Bootui Java Development (jdubois/boot-ui, 307 stars), Go (inference-gateway/inference-gateway, 214 stars) and Java 21 Developer Guide for Grails (apache/grails-core, 2.9k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains 141 Java Refactoring With Modern Features?

jabrena (a GitHub user) maintains it in jabrena/plinth, which has 446 GitHub stars. The repository holds 124 skills in this directory. The repository was last updated on October 7, 2026.

Source: jabrena/plinth on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.