141-java-refactoring-with-modern-features

141-java-refactoring-with-modern-features is a skill for Claude Code, Codex from jabrena/cursor-rules-examples. It costs 94 tokens per session (526 once invoked), scanned A, original, Apache-2.0.

A guide for updating Java code with features introduced from Java 8 onward, such as lambdas, streams, safer handling of missing values, and modern date APIs. It also covers newer Java syntax and collection features.

In plain words
What is it for?
Use it when reviewing or refactoring Java classes, loops, date handling, null checks, collections, multi-line strings, or newer Java 25 code.
Why use it?
It helps replace older, longer patterns with clearer modern Java code while checking that the project compiles before and after the changes.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/jabrena/cursor-rules-examples/141-java-refactoring-with-modern-features
Any agent
npx skills add jabrena/cursor-rules-examples --skill 141-java-refactoring-with-modern-features
Clone the repo
git clone --depth 1 https://github.com/jabrena/cursor-rules-examples

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for 141-java-refactoring-with-modern-features

README.md
[![agentmods](https://agentmods.dev/badge/skills/jabrena/cursor-rules-examples/141-java-refactoring-with-modern-features.svg)](https://agentmods.dev/skills/jabrena/cursor-rules-examples/141-java-refactoring-with-modern-features)
Your own site
<a href="https://agentmods.dev/skills/jabrena/cursor-rules-examples/141-java-refactoring-with-modern-features"><img src="https://agentmods.dev/badge/skills/jabrena/cursor-rules-examples/141-java-refactoring-with-modern-features.svg" alt="Measured on agentmods" height="20"></a>
Per session 94 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 526 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00094 $0.00526
Opus 5 $0.00047 $0.00263
Sonnet 5 $0.00019 $0.00105
Haiku 4.5 $0.00009 $0.00053

Measured 4d ago against content hash 4dafdd4f41b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

141-java-refactoring-with-modern-features scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/141-java-refactoring-with-modern-features/SKILL.md · 44 lines

What it actually says

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

When to use this skill

  • Review Java code for modern Java development
  • Apply best practices for modern Java development in Java code

Reference

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

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 44 lines · 94 tokens per session scan A 4dafdd4f41b8

Subscribe to this mod's changes

141-java-refactoring-with-modern-features is a skill published in the GitHub repository jabrena/cursor-rules-examples (2 stars, last pushed 8d ago), licensed Apache-2.0. It adds 94 tokens to every session and 526 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.