Learn CHEERPJ with Real Code Examples

Download or import CheerpJ runtime

Place .jar or .class files in project

Use cheerpjRun() or cheerpjInit() in HTML

Deploy runtime + assets to server

Load application via Java entry point

Install Java/JDK

Download CheerpJ runtime

Prepare JAR files

Set up index.html loader

Deploy to modern browser environment

index.html - launcher

cheerpj.js - main runtime script

cheerpj-*.wasm - wasm modules

app.jar - your Java code

config.json - optional configuration

java -jar yourapp.jar - test locally

cheerpjify - compile Java to JS/Wasm (AOT)

serve static site - deploy

browser DevTools - runtime debugging

bundle assets - optimize startup

Java’s built-in ResourceBundle supported

UTF-8 fully supported

Locale settings inherited from Java runtime

Dynamic string replacement supported

External i18n libraries compatible

Accessibility depends on Swing implementation

Canvas limits native browser accessibility

Use keyboard events for navigation

Screen-reader support limited

Best for internal enterprise tools

Swing look and feel preserved

Custom themes rely on Java LAF

Canvas-based rendering only

CSS styling limited (UI not DOM-native)

Custom drawing via Graphics2D

Java objects stored in CJRE heap

UI state maintained in Swing components

Event dispatch loop inside CJRE

Virtual filesystem for persistence

Optional JS callbacks for state bridging

Java I/O APIs backed by browser storage

Use Java JSON libraries normally

Network access via Java HTTP APIs

Local storage mapped to virtual FS

External resources loaded via JS