Java API Consistency Validator Agent Skill

Validate API consistency between two versions of Java libraries. Use when you need to compare API behavior, signatures, and exceptions between Java library versions to identify breaking changes, incompatible modifications, and behavior differences. The skill performs static analysis of Java code, compares method signatures, class definitions, interface changes, parameter types, return types, exception declarations, and generates a detailed JSON report with breaking changes, warnings, and migration guidance. Supports Java libraries and packages.

3k tokens

context cost

the whole folder, loaded on every use

files

ships runnable scripts

copies elsewhere

how many repositories repackaged it

141

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/ArabelaTso/Skills-4-SE --skill java-api-consistency-validator

The instruction itself

7 sections, as written by the author

Java API Consistency Validator

Overview

This skill validates API consistency between two versions of Java libraries by comparing signatures, behavior, and exceptions. It identifies breaking changes, incompatible modifications, and provides detailed reports to guide safe API migration or upgrade.

Quick Start

# Compare two versions of a Java library
python scripts/validate.py /path/to/old_version /path/to/new_version

# Specify output file
python scripts/validate.py old_lib/ new_lib/ --output report.json

What Gets Validated

Method Signatures - Parameters, return types, modifiers
Class Definitions - Methods, inheritance, interfaces
Interface Changes - Method additions, removals
Parameter Changes - Added, removed, or modified parameters
Return Type Changes - Modified return types
Exception Declarations - throws clauses
Removed APIs - Deleted classes, interfaces, or methods

Validation Report

The tool generates a JSON report with:

Breaking Changes: API removals, incompatible modifications
Warnings: Type changes, signature modifications
Info: New additions, non-breaking changes
Summary: Total issues by severity

Example report:

{
  "summary": {
    "breaking_changes": 3,
    "warnings": 5,
    "info": 2
  },
  "breaking_changes": [
    {
      "type": "method_removed",
      "class": "UserService",
      "method": "getUser",
      "severity": "breaking",
      "message": "Method 'UserService.getUser' was removed"
    }
  ]
}

Usage

python scripts/validate.py <old_version_path> <new_version_path> [--output <report.json>]

The validator exits with code 1 if breaking changes are found, 0 otherwise.

Tips

Run validation before upgrading dependencies
Review breaking changes carefully
Check warnings for potential issues
Use in CI/CD pipelines to catch API changes
Compare against semantic versioning expectations
Validate before releasing new library versions

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How to use it

Copy the folder

Take arabelatso/java-api-consistency-validator from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.