Installation

Installation Guide

Download and install LeanJ from GitHub Releases. Get up and running in minutes.

Prerequisites

• Java JDK 11+ - Required for profiling Java applications
• IntelliJ IDEA 2023.1+ (optional) - For IDE integration

Step 1: Download from GitHub Releases

1. Go to GitHub Releases
2. Download the latest release archive for your platform:
   • Windows: leanj-<version>-windows.zip
   • Linux: leanj-<version>-linux.tar.gz
   • macOS: leanj-<version>-macos.tar.gz

Step 2: Extract Files

Extract the downloaded archive. You should see the following structure:

leanj-<version>/
├── agent/
│   └── agent-core-1.0.0-SNAPSHOT.jar
├── controller/
│   └── controller-1.0.0-SNAPSHOT.jar
├── cli/
│   └── leanj.exe (Windows) or leanj (Linux/macOS)
└── intellij-plugin/
    └── leanj-1.0.0-SNAPSHOT.zip

Step 3: Add CLI to PATH

The CLI (leanj) needs to be accessible from anywhere on your system.

Windows

1. Copy leanj.exe to a directory (e.g., C:\tools)
2. Add that directory to your system PATH:
   • Open System Properties → Environment Variables
   • Edit the PATH variable
   • Add C:\tools (or your chosen directory)
   • Click OK to save
3. Restart your terminal

Alternative: Set system property in IntelliJ IDEA:

• Go to Help → Edit Custom VM Options…
• Add: -Dleanj.profiler.cli.path=C:\path\to\leanj.exe
• Restart IDE

Linux/macOS

Option 1: System-wide installation

sudo cp cli/leanj /usr/local/bin/

Option 2: User-local installation

mkdir -p ~/bin
cp cli/leanj ~/bin/
echo 'export PATH="$HOME/bin:$PATH"' >> ~/.bashrc  # or ~/.zshrc
source ~/.bashrc  # or ~/.zshrc

Step 4: Install IntelliJ Plugin

Method 1: Install from ZIP (Recommended)

1. In IntelliJ IDEA, go to File → Settings → Plugins
2. Click ⚙️ → Install Plugin from Disk…
3. Select the plugin ZIP file: intellij-plugin/leanj-1.0.0-SNAPSHOT.zip
4. Click OK
5. Restart IDE when prompted

Method 2: Install from Marketplace (If Available)

1. In IntelliJ IDEA, go to File → Settings → Plugins
2. Search for “LeanJ”
3. Click Install
4. Restart IDE when prompted

Step 5: Verify Installation

Test that everything is working:

# Check CLI is accessible
leanj --version

# Run system health check
leanj doctor

Expected output:

✓ Java: Found (11.0.19)
✓ Go: Found (1.21.0)
✓ Controller JAR: Found
✓ Agent JAR: Found
✓ Tools.jar: Found
✓ Controller: Not running (expected)
✓ Ports: Available (9876, 9877)

Troubleshooting

CLI Not Found

Error: leanj: command not found

Solutions:

1. Verify CLI is in the extracted archive
2. Check PATH includes the CLI directory
3. Restart terminal after adding to PATH
4. On Windows, verify file extension is .exe

Plugin Installation Failed

Error: Plugin won’t install or appears corrupted

Solutions:

1. Verify ZIP file is complete (check file size)
2. Try downloading the release again
3. Ensure IntelliJ IDEA version is 2023.1 or later
4. Check IDE logs: Help → Show Log in Finder

Controller JAR Not Found

Error: Controller JAR not found

Solutions:

1. Verify controller/controller-1.0.0-SNAPSHOT.jar exists in extracted archive
2. Ensure you extracted the full archive, not just the CLI
3. Check file permissions (Linux/macOS)

Agent JAR Not Found

Error: Agent JAR not found

Solutions:

1. Verify agent/agent-core-1.0.0-SNAPSHOT.jar exists in extracted archive
2. Ensure you extracted the full archive
3. Check file permissions (Linux/macOS)

File Locations

After installation, your files should be organized like this:

Windows:

C:\tools\leanj.exe          # CLI (in PATH)
C:\leanj\
  ├── agent\agent-core-*.jar        # Agent JAR
  └── controller\controller-*.jar   # Controller JAR

Linux/macOS:

/usr/local/bin/leanj         # CLI (in PATH)
~/leanj/
  ├── agent/agent-core-*.jar        # Agent JAR
  └── controller/controller-*.jar   # Controller JAR

Next Steps

• Follow the Quickstart Guide to start profiling
• Learn about IntelliJ Integration
• Explore CLI commands
• Configure advanced settings

Building from Source

If you need to build from source (for development or custom builds), see the GitHub repository for build instructions.