Lark documentation

From install to
your first program.

New to Java? Lark is an entry-level IDE designed to help you get started. The desktop packages include Java: install or extract Lark, open it, and create your first project.

Before you start

Download a complete package for your operating system from the download section. The verified desktop packages include Java; you do not need to install a separate JDK to get started.

Current verified desktop packages are x64. macOS packages are for Intel Macs; a native Apple Silicon package has not been verified. Linux packages require GNU libc. See each download’s release notes for additional details.

Windows

1. Download the recommended Windows installer.
2. Open LarkDesktopSetup.exe and follow the setup steps. The default location is %LOCALAPPDATA%\Programs\Lark.
3. Launch Lark Desktop from the Start menu or the shortcut created by setup.

Prefer a portable installation? Download the portable ZIP, choose Extract All, and open Lark.exe from the extracted folder. Keep the app and jdk folders beside it. The alternative Desktop ZIP launches with Lark Desktop.exe.

Open launchers from the extracted folder, not from a ZIP preview. Windows may show a warning for an unsigned download; verify that you downloaded the release from the official Lark GitHub repository.

macOS

1. Download the macOS desktop ZIP for Intel x64.
2. Extract the archive and keep its files together.
3. Open Launch Lark Desktop.command from the extracted folder. If the launcher needs executable permission, use Terminal to run chmod +x "Launch Lark Desktop.command" in that folder.

The included Java runtime is for Intel Macs. No native ARM64/Apple Silicon package is currently verified. Compatibility through Rosetta has not been tested for these packages.

Linux

1. Download and extract the Linux desktop ZIP on an x64 system with GNU libc.
2. Open a terminal in the extracted directory.
3. Run sh start-lark-desktop.sh. Keep the bundled app and jdk folders in place.

Update your installation

Lark checks its update feed and offers available updates in the IDE. Open Settings to review update settings and check for updates. Use the update offered for your installed edition: Desktop, Executable, or Mobile.

The published release notes describe the features available in each version. Update archives are not standalone installations. If an update fails, keep your existing installation and report the message through GitHub Issues.

Lark Flow is implemented in source. Its website screenshot comes from an authentic development build. Check your installed release notes for availability.

Your first Java project

1. Choose New project on Lark’s home screen or from the Project controls. Enter a name and choose a sample or an empty project.
2. Open a Java file in the Explorer, or use New Class to create one.
3. Write a class with a public static void main(String[] args) method. Keep any package declaration created by your project.
4. Select your class in the Main selector and click Run. Read the result in Output. If the program asks for input, type it into the input area beneath Output.

Explore Assist for Java snippets and Extras → UML diagram for a view of your project’s classes. Use the Problems panel when compilation reports an error.

Experiment with Scratch

Scratch is a separate pad for running small Java experiments. It is useful when you want to understand a calculation, condition, or loop before adding it to your project.

1. Click Scratch in the toolbar.
2. Write a few statements, such as int minutes = 25; followed by System.out.println(minutes * 60);. For a simple snippet, Lark supplies the class and main-method wrapper.
3. Click Run in Scratch, or press Ctrl+Enter. The result appears in Scratch’s own Output area.
4. Change the value and run again. Use the Scratch actions menu to create, name, or duplicate experiments. Copy copies the code; Promote turns it into a class in the current project.

Scratch runs real Java and keeps the experiment in its own editor and output area.

Understand logic with Lark Flow

1. Open Extras → Lark Flow and select a Java method.
2. Read the diagram from Start. Decision diamonds show branches; loop arrows lead back to a condition.
3. Click a node to find its source statement. Enable Follow editor to highlight diagram nodes as you move through the code.
4. Use Trace Path to choose a branch and explore a possible route. This is a static explanation of logic, not a record of program execution.
5. Pan or zoom to navigate, switch between method/class/project views, and export the diagram as PNG or SVG.

Flow is especially useful for explaining why a return ends a method, how a loop repeats, or where a condition sends the program next. Complex constructs it cannot expand accurately are explicitly marked.

Lark Mobile

Use Lark Mobile from Android, iPhone, iPad or a modern browser by connecting to a Lark Mobile host. Java compilation, program execution and debugging run on the host computer and require its JDK. Remote execution requires a Linux host with bubblewrap, util-linux and enabled user namespaces; unsupported hosts fail safely. Windows/macOS hosts support trusted local-only execution. This is not native Java execution on iOS.

Lark 4.0.5 adds per-file undo, search, rename/delete, symbol keys, breakpoints, stepping, variables and live program input. The release packages are available; physical device testing remains limited.

1. Start the Mobile host locally to create and edit projects.
2. For phone access, configure a PKCS12 HTTPS identity using -Dlark.mobile.keystore=/path/to/identity.p12 and the LARK_MOBILE_KEYSTORE_PASSWORD environment variable, then start with --lan. The browser or device must trust this certificate.
3. Open the private phone URL from the host console. Keep the host running. Pairing grants access to the host workspace; share the link only with trusted users.

Android client source and a reproducible development APK workflow are included in the repository. Download the Android development APK. It is development-signed and requires a trusted HTTPS host; device installation remains unverified. Browser access is also supported. No native iOS package is offered. Mobile Share guests join from More using a directly verified desktop invitation and host approval. Shared programs run after review on the desktop host.

Published Mobile host packages and release notes ↗

Need a hand?

Search or open a GitHub issue, or email [email protected]. Include your operating system, Lark version, and the exact error message.

Building Lark yourself? See the repository’s build instructions. Lark uses the MIT license.