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Run Java in the browser

CheerpJ Core is a WebAssembly-based Java Virtual Machine for the browser. It has extensive compatibility with Java 8, Java 11 and Java 17 (preview), and provides a full runtime environment for running Java applications, applets, libraries, and Java Web Start / JNLP applications in the browser without plugins.

Start Testing CheerpJ Core
Documentation

Run Java in the browser

CheerpJ Core is a WebAssembly-based Java Virtual Machine for the browser. It has extensive compatibility with Java 8 and Java 11, and provides a full runtime environment for running Java applications, applets, libraries, and Java Web Start / JNLP applications in the browser without plugins.

Start Testing CheerpJ Core
Documentation

Legacy Applications

CheerpJ allows organizations to preserve access to legacy Java applications (Applets, JNLPs, and stand-alone applications) by running them on the browser, without requiring a local JVM installation.

It is compatible with Java Swing, Oracle Forms, EBS, and other third-party frameworks.

With CheerpJ, you can remove the requirement for IE and Java on the client, and upgrade the accessibility and security of your application.

 

Modernise your Java Application to HTML5

 

With CheerpJ Organisations with products based on Java can migrate applications to HTML5 or the cloud with minimal or no effort, making them accessible from modern browsers, without a local Java installation.

CheerpJ allows a fully automated, full or partial migration of an existing Java client to a browser-based web application.

Integrate Java libraries into your web application

CheerpJ allows web developers to integrate Java libraries and components in native web applications.

By running Java components within the browser sandbox, developers can build a new generation of fully client-side Web applications that combine Web-native components with Java libraries to implement complex functionalities.

Built on WebAssembly, CheerpJ provides a full Java environment and OpenJDK compatibility to the browser.

Legacy Applications

CheerpJ allows organizations to preserve access to legacy Java applications (Applets, JNLPs, and stand-alone applications) by running them on the browser, without requiring a local JVM installation.

It is compatible with Java Swing, Oracle Forms, EBS, and other third-party frameworks.

With CheerpJ, you can remove the requirement for IE and Java on the client, and upgrade the accessibility and security of your application.

 

Modernise your Java Application to HTML5

 

With CheerpJ Organisations with products based on Java can migrate applications to HTML5 or the cloud with minimal or no effort, making them accessible from modern browsers, without a local Java installation.

CheerpJ allows a fully automated, full or partial migration of an existing Java client to a browser-based web application.

Integrate Java libraries into your web application

CheerpJ allows web developers to integrate Java libraries and components in native web applications.

By running Java components within the browser sandbox, developers can build a new generation of fully client-side Web applications that combine Web-native components with Java libraries to implement complex functionalities.

Built on WebAssembly, CheerpJ provides a full Java environment and OpenJDK compatibility to the browser.

Key Features

Java on the browser

CheerpJ is a Java Virtual Machine in WebAssembly, that enables modern browsers to run Java 8, Java 11 and Java 17 (preview), client-side.

Full Runtime

CheerpJ comes with a full OpenJDK runtime environment, ensuring that existing applications ‘will just work’. This includes Java Swing, AWT, and any other runtime component.

Scalable JNI Architecture

CheerpJ has extensive native method compatibility, and allows developers to ship custom natives in JavaScript / WebAssembly, providing a viable path for running complex Java applications.

Networking and System

CheerpJ provides a full networking stack (HTTP(s), TCP/IP), as well as support for file access, clipboard, audio, printing, and more.

Java-JavaScript Interoperability

CheerpJ provides multiple mechanisms for Java and JavaScript to interoperate.

Full Classloader Support

CheerpJ gives full control to the appropriate Classloader for class resolution, including application-provided ones. This ensures full compatibility with the most complex applications.

Effortless Deployment

CheerpJ does not need access to the source code at all, operating at the level of Java bytecode. Third-party libraries, dependencies and obfuscated code pose no issue.

Legacy Modernization

With CheerpJ, you can modernize access to legacy Java Applets and Applications on modern browsers, removing the requirement for IE, Edge IE mode, and for a local Java installation.

Web Development

CheerpJ powers the browser with a full Java environment, so developers can combine Java components with web-native applications.

Find the Right Plan

Whether you are just testing out CheerpJ, or integrating it into an Enterprise product with a complex deployment, we have a plan to support you.

Community (Free)

Best for: Personal projects and FOSS, technical evaluations

Get Started

✔️ Unlimited access to CheerpJ Core
✔️ For individuals and FOSS projects
✔️ Commercial use allowed

✔️ Community Support
✔️ Documentation & Guides
‎

‎

❌ Self-Hosting not allowed
❌ OEM/Redistribution not allowed

Small Business

Best for: Startups and small teams

£100 per developer per month

✔️ Unlimited access to CheerpJ Core
✔️ For teams of up to 10*
✔️ Commercial use allowed

✔️ Community Support
✔️ Documentation & Guides
✔️ Priority Support available
✔️ SLAs available
‎

✔️ Self-Hosting available
✔️ OEM/Redistribution available

* Full eligibility criteria apply.

Enterprise

Best for: Larger organizations

Contact Sales

✔️ Unlimited access to CheerpJ Core
✔️ For teams of any size
✔️ Commercial use allowed

✔️ Community Support
✔️ Documentation & Guides
✔️ Priority Support included
✔️ SLAs available
✔️ Custom onboarding & training

✔️ Self-Hosting included
✔️ OEM/Redistribution available

FAQs

Your Most Frequently Asked Questions

CheerpJ can run Java Applets, Java Web Start applications, stand-alone Java applications (including Swing), and Java libraries, on any modern browser that supports WebAssembly.

CheerpJ is the only full Java Runtime Environment for the browser, extensively compatible with Java SE and equipped with a full build of the OpenJDK JRE. By using CheerpJ, you will not need to modify your application – it will just work on any browser, without a local Java installation.

You can use CheerpJ in two scenarios:

  1. To preserve and improve access to existing legacy Java applications, including third-party ones, in the form of Java Applets, Java Web Start, or standalone. With CheerpJ, you can extend the life of mission-critical Java content, improve its security, and eliminate the need for legacy browsers and Java Desktop installations.
  2. If you are a developer, to modernise existing Java applications into web applications, without rewriting them. CheerpJ allows you to use existing Java either to develop a full application, or to preserve parts of the application (e.g. the client-side business logic) with a new HTML5 UI, breathing new life in your application with minimal investment.

Yes. CheerpJ is used by many organizations worldwide to run Oracle Java-based products, such as Oracle Forms and Oracle E-Business Suite, on modern browsers. This includes several Fortune 500 companies as well as local and federal government agencies.

CheerpJ is a full JVM in WebAssembly, running client-side within the browser sandbox. It has no native or server-side components. As such, it benefits from the Web security model, drastically improving the application security profile compared to standard Java applications.

More FAQs

Learn More About CheerpJ

Learn More About CheerpJ

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Discover how to modernize and improve access to your legacy Java applications with CheerpJ.

Schedule a free demo with our team to learn how CheerpJ can help address your Java requirements.

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