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.
npx skills add decebals/claude-code-java --skill java-migrationgit clone --depth 1 https://github.com/decebals/claude-code-javaWrote 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.
[](https://agentmods.dev/skills/decebals/claude-code-java/java-migration)<a href="https://agentmods.dev/skills/decebals/claude-code-java/java-migration"><img src="https://agentmods.dev/badge/skills/decebals/claude-code-java/java-migration/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/decebals/claude-code-java/java-migration"><img src="https://agentmods.dev/badge/skills/decebals/claude-code-java/java-migration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Prompt Injection · line 65 Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00051 | $0.03851 |
| Opus 5.5 | $0.00020 | $0.01540 |
| Sonnet 5.5 | $0.00010 | $0.00770 |
| Haiku 4.5 | $0.00005 | $0.00385 |
Grade A, and why
java-migration 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 571 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Java Migration Skill
Step-by-step guide for upgrading Java projects between major versions.
When to Use
- User says "upgrade to Java 25" / "migrate from Java 8" / "update Java version"
- Modernizing legacy projects
- Spring Boot 2.x → 3.x → 4.x migration
- Preparing for LTS version adoption
Migration Paths
Java 8 (LTS) → Java 11 (LTS) → Java 17 (LTS) → Java 21 (LTS) → Java 25 (LTS)
│ │ │ │ │
└──────────────┴───────────────┴──────────────┴───────────────┘
Always migrate LTS → LTS
Quick Reference: What Breaks
| From → To | Major Breaking Changes |
|---|---|
| 8 → 11 | Removed javax.xml.bind, module system, internal APIs |
| 11 → 17 | Sealed classes (preview→final), strong encapsulation |
| 17 → 21 | Pattern matching changes, finalize() deprecated for removal |
| 21 → 25 | Security Manager removed, Unsafe methods removed, 32-bit dropped |
Migration Workflow
Step 1: Assess Current State
# Check current Java version
java -version
# Check compiler target in Maven
grep -r "maven.compiler" pom.xml
# Find usage of removed APIs
grep -r "sun\." --include="*.java" src/
grep -r "javax\.xml\.bind" --include="*.java" src/
Step 2: Update Build Configuration
Maven:
<properties>
<java.version>21</java.version>
<maven.compiler.source>${java.version}</maven.compiler.source>
<maven.compiler.target>${java.version}</maven.compiler.target>
</properties>
<!-- Or with compiler plugin -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.12.1</version>
<configuration>
<release>21</release>
</configuration>
</plugin>
Gradle:
java {
toolchain {
languageVersion = JavaLanguageVersion.of(21)
}
}
Step 3: Fix Compilation Errors
Run compile and fix errors iteratively:
mvn clean compile 2>&1 | head -50
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.
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.
- 1mo ago First seen · 571 lines · 51 tokens per session scan A a3e398c6d9bc
java-migration is a skill published in the GitHub repository decebals/claude-code-java (753 stars, last pushed 1mo ago), licensed MIT. It adds 51 tokens to every session and 3,851 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-30.
Other skills, from other repositories
112-java-maven-plugins
Use when you need to add or configure Maven plugins in your pom.xml — including quality tools (enforcer, surefire, failsafe, jacoco, pitest, spotbugs, pmd), security scanning (OWASP), code formatting (Spotless), version management, container image build (Jib), build information tracking, and benchmarking (JMH) …
814-regulations-iso-25010
Use when reviewing, designing, or modifying Java enterprise systems and need a structured, repeatable ISO/IEC 25010:2023 quality-attribute review covering Functional Suitability, Performance Efficiency, Compatibility, Interaction Capability, Reliability, Security, Maintainability, Flexibility, and Safety, producing an…
121-java-object-oriented-design
Use when reviewing, improving, or refactoring Java object-oriented design, including applying SOLID, DRY, or YAGNI; improving classes and interfaces; correcting encapsulation, inheritance, or polymorphism; resolving God Class, Feature Envy, or Data Clumps; and improving object creation, methods, or exception…
111-java-maven-dependencies
Use when you need to add or evaluate Maven dependencies that improve code quality or domain modeling — including nullness annotations (JSpecify), static analysis (Error Prone + NullAway), functional programming (VAVR), architecture testing (ArchUnit), or money and currency support (JavaMoney) — and want a…
114-java-maven-search
Routes Maven version questions to the right workflow by choosing project-local update report interpretation for a user’s own pom.xml, or Maven artifact discovery from maintainer-approved structured evidence. Use when interpreting dependency, plugin, or property update reports; finding Maven coordinates; verifying…
041-planning-plan-mode
Use when creating or refining a structured Java implementation plan from trusted issue summaries, approved designs, ADRs, OpenSpec changes, existing plans, or a valid combination. The plan records its source artifacts and derivation direction and can remain the execution artifact without requiring OpenSpec. This…