CheerpJ is

  • the Java compiler for the Web

  • converts any Java client application into standard HTML5/WebAssembly/JavaScript

  • works from Java bytecode, without requiring access to the source code

  • compatible with 100% of Java (reflection and dynamic classes included)

  • turn-key solution, works on Java Swing clients, Java applets, and Java libraries

  • actively developed and supported by Leaning Technologies experts

CheerpJ

The solution for converting Java clients to HTML5

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100% of Java SE

Reflections, proxy classes, multi-threading are all supported thanks to unique technical solutions.

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Performance oriented

Based on both WebAssembly and highly-optimised JavaScript, CheerpJ can achieve excellent runtime performance and a small download footprint.

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Full runtime environment

Based on a full, unmodified OpenJDK runtime environment: supports Swing, Filesystem, Audio, Printing.

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First class HTML5 interoperability

Access the DOM, WebAPIs (e.g. WebGL, WebAudio) and browser resources from Java. Make Java calls from JavaScript.

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Browsers as compilation target

CheerpJ converts your Java client into a standard HTML5, automatically. No longer ask your end users to maintain a local Java installation.

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Convert or migrate

Convert full applications or individual components (such as libraries) and expose JavaScript APIs to use them from HTML5.

How it works

Three key components

Ahead-of-Time
compilation

The CheerpJ compiler processes your Java bytecode ahead of time, generating optimised JavaScript that can run on any browser.


CheerpJ Runtime

In parallel to your converted application, deploy a higly-optimised runtime in WebAssembly and JavaScript, keeping 100% of the execution client-side. Based on a full unmodified build of OpenJDK .

On-line
CheerpJ Java compiler

Whenever new classes are generated (e.g. through proxy classes), CheerpJ will convert them on the fly for you.

Thanks to these three components, CheerpJ provides a seamless experience of executing a converted Java application on any browser, fully client-side. No plugins and no installation are required from the user.

Our partnership with Leaning Technologies is a major resource for Blackbird, accelerating the development of the Blackbird editor in JavaScript editor by many months. This innovation ensures Blackbird will continue to provide best-in-class efficiency in video production workflows for the foreseeable future.

Dr Stephen Streater

R&D Director Blackbird
Get CheerpJ

Licences

CheerpJ is free to use for non-commercial purposes, as well as for technical evaluation. Any other use will require a license.

Community

  • Command line CheerpJ utilities
  • Cloud-hosted CheerpJ Runtime
  • Documentation and tutorials
  • Community support on Gitter
  • Available for technical evaluations

Essential

  • Command line CheerpJ utilities
  • Cloud-hosted CheerpJ Runtime
  • Documentation and tutorials
  • Community support on Gitter
  • Technical support from our support team
  • Available to individual developers and small businesses

Enterprise

  • Command line CheerpJ utilities
  • Cloud or Self-hosted CheerpJ Runtime
  • Documentation and tutorials
  • Community support on Gitter
  • Premium technical support from our support team
  • Access to our development team for compilation log reviews, video calls, consulting
  • Available to organisations of any size

Download CheerpJ

Why not starting with a tutorial:
How to get started with CheerpJ?

How we can help

We are experts at converting and migrating legacy Java

Demos

Examples of CheerpJ in action



Browser based Java playground

Code editor and runtime all in one. Feel free to compile some Java.

View Demo

CheerpJ Applet Runner

Our own free solution to help anyone run legacy Java Applets on Chrome without having to install Java.

Go to Chrome web store

Demo's page

CheerpJ's collections of demo, complete with source code to reproduce and modify the results.

CheerpJ demos
Documentation

Developers area

Terms & Conditions

By clicking on the ‘Download’ link, you are accepting the CheerpJ non commercial licence agreement.
I accept.

Terms & Conditions

By clicking on the ‘Download’ link, you are accepting the CheerpJ non commercial licence agreement.
I accept.

Terms & Conditions

By clicking on the ‘Download’ link, you are accepting the CheerpJ non commercial licence agreement.
I accept.