Scratch for Java Studio

Scratch for Java Studio is a desktop IDE for students moving from Scratch to Java. It builds projects with Scratch for Java and keeps them as ordinary Java source files that also work in BlueJ and VS Code.

Status: 0.1.0-alpha.12. The IDE and its project format may change while we test it with students and teachers.

• Create a project from a starter, tutorial, or demo; open an existing project folder or import a Scratch .sb3 project.
• Edit Java with completion, live diagnostics, beginner-friendly explanations in English and German, a Scratch block palette, and API help.
• Arrange stages and sprites in visual editors. Managed Java regions keep the visual editors and source code in sync while leaving other code editable.
• Edit images, sounds, sprite sheets, hitboxes, shaders, and Tiled maps.
• Run programs in a separate JVM, use the console and debugger, and export a runnable JAR, a portable app folder, or a BlueJ/VS Code project ZIP.

Student programs use the Scratch for Java library. The IDE does not replace or modify that library.

Install JDK 25 and Maven 3.9 or newer. A graphical desktop is needed to run the IDE and student programs.

mvn verify
mvn -pl app -am install -DskipTests
mvn -pl app exec:java

Run exec:java with -pl app only: the parent project has no main class. After changing source code, repeat the install command and restart the IDE so exec:java uses the updated modules in your local Maven repository.

Run the packaging script on the target operating system. It includes a JetBrains Runtime for the IDE and student programs, so users do not need to install a JDK. The same runtime supports enhanced hot reload.

scripts/package-ide.sh app-image  # portable application folder
scripts/package-ide.sh deb        # Linux package
scripts/package-ide.sh msi        # Windows installer, on Windows
scripts/package-ide.sh dmg        # macOS disk image, on macOS

Outputs are written to target/package/. The GitHub Actions Package IDE workflow builds platform artifacts when run manually or when an alpha tag is pushed. Packaging may download the Scratch for Java library and a JetBrains Runtime. Signing and notarization require the corresponding CI secrets.

The six Maven modules are core (projects and editing logic), runner (separate JVM execution), sound, export, ui (JavaFX), and app (entry point and packaging).

The IDE is MIT licensed. Bundled Scratch for Java artwork and sounds come from Kenney under CC0. OGG and MP3 support uses replaceable LGPL libraries; RichTextFX, AtlantaFX, Ikonli, and Feather icons retain their respective licenses.

Open a browser workspace JSON or portable project ZIP through the Project menu. Export a Browser project ZIP to continue in an embedded IDE revision with ZIP support. Code, assets, flavor and lesson identity travel with the project. NRW course classes remain ordinary source on desktop and are retained in the browser.

Use Project > Import course pack for the offline tutorial/Spielwerkstatt pack. Run > Run behavior checks executes transferred browser test classes with bundled JUnit, leaving their source unchanged. Scratch imports have a Scratch migration tab linking timing/unsupported-block tasks to the original block and Java source; the original .sb3 remains in the project.

Run all checks locally with scripts/test.sh, or pick stages:

scripts/test.sh unit          # mvn verify (CI runs this on Linux, Windows and macOS)
scripts/test.sh smoke         # OpenGL, UI and export smoke (CI runs this on Linux)
scripts/test.sh integration   # release catalogs, course pack, browser transfer

Integration is local only: it uses sibling checkouts of scratch-for-java (at the bundled release tag, via a temporary worktree), hyperbook-informatik and online-ide; set SCRATCH_LIBRARY, CURRICULUM or ONLINE_IDE to use other paths. Run it before a release or after changing templates, export or import. The course check imports and compiles all 18 projects and runs the score tests. Use --libraries /path/to/bundled/library for a fully offline check. The native packaging workflow runs scripts/smoke-packaged.py on each supported OS. Local Linux validation uses Xvfb when no display is available.