Run Java applications
in the browser

No plugins. No desktop installs. No application rewrite required.

POWERING ENTERPRISE SOFTWARE

Your Java applications still work.

CheerpJ makes sure they keep working.

Rewriting critical systems is expensive, risky, and rarely necessary. CheerpJ runs Java applications in the browser, preserving your investment while simplifying deployment.

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https://apps.company.com/forms/ap_invoice.fmx?runtime=cheerpj

Oracle Forms Services - Accounts Payable

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Invoice Workbench

Invoice Approval

Session: FIN-OPS-2048

Supplier

Northbridge Industrial Components Ltd

Invoice Number

INV-104893

Invoice Date

16 Mar 2026

Currency

GBP

Description

Monthly hardware maintenance contract and replacement parts for regional branch systems.

Line	Cost Centre	Description	Amount	Status
001	FIN-221	Maintenance services	£31,200	Validated
002	OPS-118	Replacement hardware	£9,880	Validated
003	IT-074	Shipping	£1,500	Pending

Loading Oracle Forms

Java application running in browser via CheerpJ

72%

CJ

CheerpJ is loading Oracle Forms

Initializing Java runtime, loading application classes, and starting the Oracle Forms session directly inside the browser.

Loading runtime and application assets 72%

LEGACY MODERNIZATION

Extend the life of legacy Java apps with CheerpJ

CheerpJ runs Java applications in modern browsers without a local Java installation. It ships a full OpenJDK environment and supports Swing and AWT UIs, plus frameworks such as Oracle Forms and Oracle EBS.

Removing local Java installs and legacy browser dependencies reduces client-side risk and support overhead.

ARCHITECTURE

How CheerpJ runs Java applications in the browser

CheerpJ runs standard Java applications directly in the browser using WebAssembly. It provides a full OpenJDK runtime and Java Virtual Machine that executes Java bytecode without plugins, desktop installations, or source code changes.

1. Java Runtime in the Browser

CheerpJ includes a full OpenJDK runtime compiled to WebAssembly and JavaScript. It supports Java 8, Java 11, and Java 17 applications and runs entirely inside modern browsers.

3. Interpreter + JIT Optimization

Java bytecode starts in an interpreter, while frequently used code is compiled Just-in-Time into optimized JavaScript for higher performance.

2. JVM Executes Java Bytecode

Applications are loaded as standard JAR, class, or WAR deployments. CheerpJ executes the bytecode using a browser-based Java Virtual Machine.

4. Browser Integration Layer

CheerpJ provides system services needed by enterprise applications, including virtual file system support, HTTP networking, Java ↔ JavaScript interoperability, and AWT/Swing rendering through HTML Canvas.

DEPLOYMENT

Easily deploy CheerpJ

CheerpJ is delivered as static WebAssembly and JavaScript assets. It can be hosted on any web server or CDN and integrated into a page with a simple <script> tag. No browser plugins or server-side components are required.

view-source:https://yourdomain.com/javaapp

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view-source:https://yourdomain.com/javaapp

index.html

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PLATFORM SUPPORT

Enterprise Java compatibility

CheerpJ provides a browser-based JVM built on OpenJDK, with full Java language compatibility and bytecode-level execution. Supports standard JAR and WAR deployments, including Swing and AWT applications, without requiring a client-side JVM.

Java Versions

✔️ 8, 11, 17 (preview)
✔️ Java bytecode execution in the browser
✔️ Full Java runtime delivered client-side (WebAssembly-based)
✔️ Use for long-running applications that are difficult to rewrite

UI and graphics

✔️ Standard Swing/AWT widgets
✔️ Multiple windows within the application UI
✔️ Typical enterprise UI workflows (forms, tables, dialogs)

Networking

✔️ HTTP/HTTPS networking
✔️ Backend services remain unchanged
✔️ Works with existing application APIs and service endpoints

Deployment

✔️ On-premise
✔️ Controlled enterprise environments

PRODUCT SUITE

Explore our Java execution tools for the browser

CheerpJ Core

The main CheerpJ tool for developers. A JVM / OpenJDK distribution in JavaScript and WebAssembly. Runs full Java apps and libraries in the browser.

Learn More

CheerpJ JNLP Runner

An end-user tool to run Java Web Start apps in Chrome or Edge – without installing Java locally. Perfect for legacy enterprise applications.

Learn More

CheerpJ Applet Runner

An end-user tool to run Java Applets on modern browsers. Works instantly on Chrome or Edge, no code changes required.

Learn More

Request a demo

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.

Fill in the form or book a demo directly here

RESOURCES

Run Java applications
in the browser

Your Java applications still work.

CheerpJ makes sure they keep working.

Extend the life of legacy Java apps with CheerpJ