CheerpJ is a WebAssembly-based Java Virtual Machine for modern browsers.
🎯Broad Compatibility – Supports Java 8* and earlier. Java 11+ coming in 2025.
🖥️Rich UI Support – Runs Swing, AWT, Oracle Forms, and EBS apps in the browser.
🔒Secure & Isolated – No access to host system. Ideal for enterprise and compliance.
🧰Full System Integration – Clipboard, networking, file access — all from your browser.
*Tested on Oracle Forms, EBS, Swing, AWT, and standard frameworks.
Not sure where to start?
Get Started Based on Your Role
Build with Java & WebAssembly
for modern platforms — no plugin needed.
Improve accessibility and eliminate
dependency on legacy Java setups.
Reduce rewrite costs and modernize
Java apps without code changes.
CheerpJ: The JVM for Modern Browsers
Run full Java applications, applets, and libraries entirely in the browser – no installation needed. Ideal for complex applications and long-term projects.
Use Cases:
🖥️Legacy Swing/Desktop applications
📱Cross-platform enterprise tools
🎓Java educational platforms and training apps
🛠️Browser-based deployment for internal software
Instantly run Java Web Start (JWS) apps in Chrome or Edge – without installing Java locally. Perfect for legacy enterprise tools.
Use Cases:
🧾Launch .jnlp files in modern browsers
🏢Replace deprecated Java Web Start workflows
🧪Scientific and technical software delivery
🌐Web-based access to internal dashboards
Bring your legacy Java applets back to life in modern browsers. Works instantly on Chrome or Edge, no code changes required.
Use Cases:
🧱Restore embedded applets on legacy websites
💹Financial/trading platforms with applet UIs
🎓Educational tools, calculators, and simulations
🗃️Preserve or maintain institutional Java content
Not sure where to start? Find the right tool for you.
We’re building the future of Java in the browser. Here’s what’s coming:
| Feature | Availability | Status |
|---|---|---|
| Java 11 Support | Available in nightly builds | 🟢 Preview Ready |
| WebAssembly JNI Modules | Available in preview (on demand) | 🟢 Preview Ready |
| Improved Mobile Usability | Available in nightly builds | 🟢 Improving |
| Java 17 Support | Planned for 2025 | 🟡 In Development |
| JavaFX Support | Planned | 🟡 On the Roadmap |
A superb extension with great customer support! We have an large, extensive applet that displays automated weather reports from commercial aircraft that is used by weather services world-wide. Thanks to CheerpJ we can now run it again in a browser (chrome). The CheerpJ version is FAST, able to display 800,000+ wind barbs in just a couple of seconds. We’re very happy indeed.
Fantastic job. My large JAVA applet for a visual interactive discovery of derivatives and integrals of vector fields had been used all around the world for almost 20 years — then the browsers effectively killed it by withdrawing support for JAVA. I had not been able to rewrite it as a freestanding JAVA main program. So happy when I discovered CheerpJ in the spring. So many happy students, instructors, and folks from everywhere who just to play and discover!
Matthias Kawski
This is great! I had a set of online “animated diagrams” as Java applets since about 1999. Over the years, support for Java in browsers has disappeared due to security concerns. Now I can see my old applets again.
Craig Reynolds
Simply amazing simplicity and effectiveness. Very useful with old switches that only have a Java Applet interface and other similar appliances. Great job!
Gianluca Bonetti
The Java Applet I am using looks and behaves very similarly under CheerpJ on a modern computer, vs an ancient computer with an old browser that actually runs Java applets. Performance is good, too. Five stars!
Leaning Technologiesは、ソフトウェアへにおける究極の難題をサポートするため、そのツールセットを拡張する十分な能力と、要求される完璧なレベルを達成するという揺るぎない決意を兼ね備えていました。激務だったが、Blackbirdは比較的短い期間でHTMLプロダクトを世界中のクラアントに発信することができました
Stephen Streater
Blackbird plc R&Dディレクター
CheerpJ を使用して、レガシー Java アプリケーションを最新化し、アクセスを改善する方法をご覧ください。
CheerpJ が Java 要件への対応にどのように役立つかを知るには、弊社のチームによる無料デモをスケジュールしてください。
フォームに記入するか、直接デモを予約してください こちらをご覧ください。
日本語 
English (UK)