jbuild

Cargo for Java - A modern, fast, and user-friendly build system for Java projects.

The Problem

Java developers face significant friction with existing build tools:

• Slow startup: Maven takes 500ms+ and Gradle 1000ms+ just to start, even for simple commands
• High memory usage: JVM-based tools consume 200-300MB+ of RAM
• Complex configuration: Verbose XML (Maven) or DSL learning curve (Gradle)
• Poor developer experience: No simple add dependency command, manual XML editing required
• Tool fragmentation: Different commands and concepts between Maven and Gradle

Every mvn compile or gradle build wastes seconds waiting for the JVM to start.

The Solution

jbuild is a native Rust implementation that brings the Cargo experience to Java:

Key Advantages

1. 50x Faster Startup - Native binary, no JVM warmup
2. 5x Less Memory - Efficient Rust implementation
3. Unified CLI - Same commands for Maven and Gradle projects
4. Modern UX - Simple commands like add, remove, search, tree
5. Zero Config - Works with existing pom.xml or build.gradle
6. Code Quality Built-in - Integrated Checkstyle linting

Quick Start

# Install (coming soon)
cargo install jbuild

# Create a new project
jbuild new my-app
cd my-app

# Build and run
jbuild build
jbuild run                    # Auto-detect and run main class
jbuild run --main-class com.example.App  # Specify main class
jbuild run arg1 arg2          # Pass arguments to application

# Manage dependencies
jbuild search slf4j              # Search Maven Central
jbuild add org.slf4j:slf4j-api:2.0.9
jbuild remove org.slf4j:slf4j-api
jbuild tree                      # Show dependency tree
jbuild info org.slf4j:slf4j-api  # Show package details
jbuild outdated                  # Check for outdated dependencies
jbuild update                    # Update all dependencies

Code quality

jbuild lint # Run Checkstyle checks jbuild test # Run tests

## Usage

### Project Management
```bash
jbuild new my-app                # Create new Maven project
jbuild new my-app -b gradle      # Create new Gradle project
jbuild new my-lib -t lib         # Create library project
jbuild init                      # Initialize in existing directory

Workspace Support (Multi-Project Builds)

jbuild workspace new my-workspace     # Create new workspace
cd my-workspace
jbuild new core -t lib                # Create core library
jbuild new app                        # Create application
jbuild workspace add core             # Add projects to workspace
jbuild workspace add app
jbuild workspace list                 # List workspace members
jbuild workspace build                # Build all projects in dependency order
jbuild workspace build compile        # Build with specific goals

Building & Running

jbuild build                     # Compile + test + package
jbuild compile                   # Compile only
jbuild check                     # Check code (compile without artifacts)
jbuild test                      # Run tests
jbuild run                       # Build and run main class
jbuild watch                     # Watch for changes and auto-rebuild
jbuild watch --test              # Watch and run tests on change
jbuild                       # Uses pom.xml/build.gradle or jbuild.toml (auto-converts to pom)
jbuild clean                     # Clean build outputs

Dependency Management

jbuild add group:artifact              # Add dependency (auto-detects latest version)
jbuild add group:artifact:version      # Add dependency with specific version
jbuild add group:artifact --dev        # Add test dependency
jbuild remove group:artifact           # Remove dependency
jbuild tree                            # Show dependency tree
jbuild tree                            # Shows transitive dependencies
jbuild search <query>                  # Search Maven Central
jbuild info group:artifact             # Show package details and versions
jbuild outdated                        # Show outdated dependencies
jbuild update                          # Update all dependencies to latest
jbuild update group:artifact           # Update specific dependency
jbuild info group:artifact             # Show package details and versions

Configuration

# Use jbuild.toml (auto-converted to pom.xml for build execution)
cat > jbuild.toml <<'EOF'
[package]
name = "my-app"
version = "0.1.0"
java = "17"

[dependencies]
"org.slf4j:slf4j-api" = "2.0.9"

[dev-dependencies]
"org.junit.jupiter:junit-jupiter" = "5.10.0"
EOF

jbuild build   # will generate pom.xml from jbuild.toml if no pom/build.gradle present
# jbuild.lock is auto-created from jbuild.toml for reproducible builds

Workspace Configuration

# jbuild-workspace.toml - Workspace configuration
members = [
    "core",
    "api",
    "app"
]

default_members = [
    "core",
    "app"
]

[resolver]
version_resolution = "Highest"  # Highest, Lowest, Fail
conflict_resolution = "Highest" # Highest, Lowest, Fail

[package]
name = "my-workspace"
version = "1.0.0"
description = "Multi-project Java workspace"

Code Quality

jbuild lint                      # Run Checkstyle (9 checks)
jbuild lint -c checkstyle.xml    # Use custom config
jbuild lint src/main/java        # Check specific directory

Comparison: jbuild vs Maven vs Gradle

Project Structure

The project is organized as a single crate with all modules under src/:

• model/: POM/Gradle file parsing and data structures
• artifact/: Artifact handling and coordinates
• core/: Core execution engine and lifecycle
• resolver/: Dependency resolution
• settings/: Settings and configuration management
• plugin_api/: Plugin API definitions
• compiler/: Java compiler integration (javac invocation, classpath management)
• packaging/: JAR/WAR file creation and packaging
• testing/: Test discovery, execution, and reporting
• main.rs: Command-line interface

Status

This is an ongoing project. Both Maven and Gradle support are implemented with shared infrastructure.

Key Features Implemented:

• ✅ Maven POM parsing and model building
• ✅ Dependency resolution (local and remote repositories)
• ✅ Plugin loading and descriptor parsing
• ✅ Plugin dependency resolution
• ✅ Java compiler integration
• ✅ Lifecycle execution framework
• ✅ Plugin execution framework (with classpath setup)
• ✅ JNI integration for Java plugin execution (optional feature)
• ✅ External Maven process fallback for plugin execution
• ✅ JAR/WAR file packaging with manifest generation
• ✅ Test discovery and execution (JUnit, TestNG)
• ✅ Test reporting
• ✅ Profile activation logic
• ✅ Property interpolation
• ✅ Model validation
• ✅ Advanced dependency resolution (version ranges, conflicts, exclusions)
• ✅ Build optimization (incremental compilation, parallel execution)
• ✅ Plugin compatibility and configuration inheritance
• ✅ Gradle build script parsing (Groovy/Kotlin DSL)
• ✅ Gradle task execution (clean, compileJava, test, jar, build)
• ✅ Build system detection and unified CLI
• ✅ Gradle dependency resolution (integrated with shared resolver)
• ✅ Multi-project builds (settings.gradle support)
• ✅ Checkstyle integration (jbuild lint command with 9 checks)
• ✅ 469 tests passing (unit, checkstyle, CLI commands, integration)

See TODO.md for the current list of remaining work items and MIGRATION.md for migration details.

Example Projects

The examples/ directory contains sample projects demonstrating jbuild capabilities:

Maven Examples

examples/
├── simple-java-project/     # Single-module Maven project
│   ├── pom.xml
│   └── src/main/java/...
└── multi-module-maven/      # Multi-module Maven project
    ├── pom.xml              # Parent POM
    ├── core/                # Core utilities module
    ├── api/                 # API interfaces module
    └── app/                 # Application module

Sample Maven POM (examples/simple-java-project/pom.xml):

<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>simple-java-project</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>
    
    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
    </properties>
    
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

Gradle Examples

examples/
├── simple-gradle-project/   # Single-module Gradle project
│   ├── build.gradle
│   └── src/main/java/...
└── multi-module-gradle/     # Multi-module Gradle project
    ├── settings.gradle      # Project settings
    ├── build.gradle         # Root build script
    ├── core/                # Core utilities module
    ├── api/                 # API interfaces module
    └── app/                 # Application module

Sample Gradle build script (examples/simple-gradle-project/build.gradle):

plugins {
    id 'java'
}

group = 'com.example'
version = '1.0.0'

sourceCompatibility = '11'
targetCompatibility = '11'

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'junit:junit:4.13.2'
}

Sample settings.gradle (examples/multi-module-gradle/settings.gradle):

rootProject.name = 'multi-module-gradle'

include ':core'
include ':api'
include ':app'

Building

# Build without JNI (uses external Maven process for plugins)
cargo build --release

# Build with JNI support (enables direct Java class loading)
cargo build --release --features jni

Running

# Modern Cargo-like commands (auto-detects build system)
jbuild build          # Compile the project
jbuild run            # Build and run main class
jbuild test           # Run tests
jbuild clean          # Clean build outputs
jbuild lint           # Check code style (Checkstyle)

# Dependency management
jbuild add org.slf4j:slf4j-api          # Add dependency (latest version)
jbuild add org.slf4j:slf4j-api:2.0.9    # Add specific version
jbuild remove org.slf4j:slf4j-api       # Remove dependency
jbuild tree                              # Show dependency tree
jbuild outdated                          # Show outdated dependencies

# Project creation
jbuild new my-app                        # Create new app project
jbuild new my-lib --template lib         # Create new library project
jbuild init                              # Initialize in existing directory

# Legacy mode (explicit build file)
jbuild --file pom.xml compile
jbuild --file build.gradle build

# Generate shell completions
jbuild completions bash > /etc/bash_completion.d/jbuild
jbuild completions zsh > ~/.zsh/completions/_jbuild
jbuild completions fish > ~/.config/fish/completions/jbuild.fish

Supported Tasks/Goals

Code Quality: jbuild lint

The lint command runs Checkstyle checks on Java source files:

# Check all Java files in src/main/java and src/test/java
jbuild lint

# Check specific files or directories
jbuild lint src/main/java
jbuild lint src/main/java/com/example/App.java

# Use custom Checkstyle configuration
jbuild lint -c checkstyle.xml

Available Checks:

• EmptyCatchBlock - Detects empty catch blocks
• EmptyStatement - Detects empty statements (standalone semicolons)
• MissingSwitchDefault - Detects switch statements without default case
• MultipleVariableDeclarations - Detects multiple variable declarations per statement
• SimplifyBooleanReturn - Detects boolean returns that can be simplified
• PackageName - Validates package naming conventions
• TypeName - Validates type naming conventions
• RedundantImport - Detects redundant imports
• LineLength - Detects lines exceeding maximum length (default: 120)

Testing

The project includes comprehensive unit tests and integration tests:

# Run all tests
cargo test

# Run only unit tests
cargo test --lib

# Run integration tests
cargo test --test example_project

# Run with output
cargo test -- --nocapture

Test Structure

• Unit tests: Located in src/ modules with #[test] attributes
• Integration tests: Located in tests/ directory
• Mocks and fixtures: src/testing_utils.rs provides mock implementations for testing

Testing Utilities

The codebase provides several testing utilities in testing_utils:

• MockArtifactRepository: In-memory artifact repository for testing
• MockDependencyResolver: Mock dependency resolver for controlled testing
• TestProjectBuilder: Fluent builder for creating test projects

Example usage:

use jbuild::{MockArtifactRepository, ArtifactRepository};

#[test]
fn test_artifact_resolution() {
    let repo = MockArtifactRepository::new();
    repo.add_artifact("com.example", "lib", "1.0.0", "/path/to/lib.jar".to_string());
    
    assert!(repo.exists("com.example", "lib", "1.0.0"));
}

Architecture & Design

See ARCHITECTURE.md for detailed architecture documentation.

The architecture is inspired by Gradle's platform-based design. See GRADLE_LEARNINGS.md for architectural patterns we're adopting.

Key Design Patterns

• Trait-based abstractions: Core components use traits for testability
• Builder patterns: Complex objects use fluent builders
• Custom error types: Comprehensive error handling with MavenError
• Dependency injection: Supports mock implementations for testing

License

Licensed under the Apache License, Version 2.0.