CodeChecker

Java-based Code Linter and Cyclomatic Complexity Analyzer

• Workflow Runs

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CodeChecker in Action 🚀

Below is a live demonstration of CodeChecker running in the terminal and printing analysis results in real time.

Have a sneak-peek 😉

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Project Overview

CodeChecker is a professional-grade Java code analysis tool designed for learning, portfolio, and profile-building purposes.
It provides code style checks and cyclomatic complexity analysis for Java source files, giving developers insights into code quality, readability, and maintainability.

This project is particularly useful for:

• Developers wanting to understand code quality metrics
• Demonstrating GitHub portfolio projects with clean code, automation, and CI/CD
• Engineering Students learning system design and building real-time projects

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Features

1. Code Style Checks

   • IndentationChecker: Detects tabs and non-multiples-of-4 spaces
   • TodoChecker: Detects TODO and FIXME comments
   • TrailingWhitespaceChecker: Detects trailing spaces at the end of lines

2. Cyclomatic Complexity Analysis

   • SimpleCyclomaticComplexityChecker: Returns file-level cyclomatic complexity
   • AdvancedCyclomaticComplexityChecker: Calculates method-level complexity and total file complexity

3. Professional Console Output

   • Only prints issues if they exist
   • Clean and readable reports for all checks

4. GitHub Actions CI

   • Automatically compiles all Java files on push
   • Runs the linter on a sample test file (ComplexityTest.java)
   • Provides a green check if compilation succeeds

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Demo Output

Example output when running CodeChecker on ComplexityTest.java:

Simple Cyclomatic Complexity:
Total Complexity: 10

Advanced Cyclomatic Complexity per method:
Method: main → Complexity: 10
File Total Complexity: 10

No code style issues found!

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Getting Started

Prerequisites

• Java 17+ installed
• Git installed
• Command-line access

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Clone Repository

git clone https://github.com/MANISH-K-07/CodeChecker.git
cd CodeChecker

Compile Java Files

javac src/*.java

• Compiles all .java files in src/

Run CodeChecker

java -cp src/main/java Main src/ComplexityTest.java

• Main.java is the entry point
• Replace ComplexityTest.java with any Java file you want to analyze

JSON Output

You can now generate machine-readable JSON output with the --json flag:

java -cp src/main/java Main <filepath> --json

Example:

java -cp src/main/java Main src/ComplexityTest.java --json

Sample JSON Output:

{
  "file": src/ComplexityTest.java,
  "indentationIssues": [],
  "todoIssues": [],
  "trailingWhitespaceIssues": [],
  "simpleCyclomaticComplexity": 10,
  "advancedCyclomaticComplexityTotal": 10,
  "advancedCyclomaticComplexityPerMethod": {main=10},
  "anyIssues": false
}

Notes:

• anyIssues only tracks real style/code issues (indentation, TODOs/FIXME, trailing whitespaces). Cyclomatic complexity is always reported but doesn’t affect this flag.

• advancedCyclomaticComplexityPerMethod provides method-level complexity, while advancedCyclomaticComplexityTotal is the sum for the file.

Checks Performed:

1. Indentation

2. TODO/FIXME Comments

3. Trailing Whitespace

4. Simple Cyclomatic Complexity

5. Advanced Cyclomatic Complexity (per method and total)

Run GitHub Actions CI

• The workflow automatically runs on every push to main
• Compiles all Java files and runs CodeChecker on the test file
• Console output is visible in the Actions tab on GitHub

Folder Structure

CodeChecker/
│
├─ src/
│   ├─ main/
│   │   └─ java/
│   │       ├─ Main.java
│   │       ├─ IndentationChecker.java
│   │       ├─ TodoChecker.java
│   │       ├─ TrailingWhitespaceChecker.java
│   │       ├─ SimpleCyclomaticComplexityChecker.java
│   │       ├─ AdvancedCyclomaticComplexityChecker.java
│   │       └─ JsonReportGenerator.java
│   │
│   └─ ComplexityTest.java
│
├─ .github/
│   └─ workflows/
│       └─ java-ci.yml
│
└─ README.md

Tech Stack

• Java 17
• GitHub Actions (CI/CD)
• Standard Java libraries (no external dependencies)

Portfolio

This project demonstrates:

• Practical knowledge of Java and software engineering principles
• Understanding of code quality metrics and complexity analysis
• Ability to create professional, automated, and well-documented projects for GitHub portfolios

License

This project is open-source and available under the MIT License.

🚧 Roadmap & Future Enhancements

CodeChecker is designed with extensibility and scalability in mind. The following enhancements outline how the tool can evolve into a full-fledged static analysis framework.

Planned Enhancements

• Multi-file and Project-level Analysis

  • Analyze entire Java projects instead of a single file
  • Aggregate complexity and style metrics across packages

• AST-based Static Analysis

  • Replace keyword-based parsing with Abstract Syntax Tree (AST) analysis
  • Improve accuracy using libraries such as JavaParser
  • Enable detection of deeper structural issues

• Integration with Existing Tools

  • Support selected rules from Checkstyle and PMD
  • Allow users to enable/disable rules selectively

• Configuration File Support

  • Introduce a codechecker.config.json file
  • Allow customization of:
    • Indentation rules
    • Complexity thresholds
    • Enabled/disabled checks

• JUnit-based Test Suite

  • Add automated unit tests for all checkers
  • Improve reliability and regression detection
  • Integrate test execution into GitHub Actions CI

• Package and Module Awareness

  • Support Java package structures
  • Enable package-level complexity and style summaries

• Machine-readable Output

  • Provide JSON output for CI/CD and toolchain integration ✔
  • Enable IDE plugins and external dashboards

Long-term Vision

The long-term goal of CodeChecker is to evolve into a lightweight, configurable static analysis tool that can be easily integrated into developer workflows, CI pipelines, and educational environments.

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