---
title: Demos
---

To showcase the capabilities of the CheerpJ compiler we have published several demos

## OpenAstexViewer

https://cheerpjdemos.leaningtech.com/OpenAstexViewer.html

<img src="https://www.leaningtech.com/assets/img/leaningtech/demo_openastex.png" width="400">

This demo highlights how complex Java applets with 3D rendering can efficiently and safely run in any browser using CheerpJ.

This specific applet is a visualization tool for protein structures, the source code is available here: https://github.com/openastexviewer/openastexviewer

## Swing examples:

https://cheerpjdemos.leaningtech.com/SwingDemo.html

<img src="https://oldsite.leaningtech.com/cheerpj/images/demo_1_swing.png" width="400">

A few selected Java Swing examples to demonstrate how complex Swing GUI apps can be automatically converted to HTML5/JavaScript.

Source: https://docs.oracle.com/javase/tutorial/uiswing/examples/components/index.html

## JavaFiddle

https://javafiddle.leaningtech.com/

<img src="https://oldsite.leaningtech.com/cheerpj/images/demo_4_fiddle.png" width="400">

A playground to compile and run Java programs directly in the browser. Both console and GUI applications are supported. The standard ```javac``` compiler is used, since ```javac``` is also written in Java the whole compiler runs in the browser, together with the compiled application.
Source: https://javafiddle.leaningtech.com/index.html (Inspect the page using the devtools)

## iText Demo

https://cheerpjdemos.leaningtech.com/iTextDemo.html

<img src="https://oldsite.leaningtech.com/cheerpj/images/demo_5_itext.png" width="400">

Edit PDFs fully client side using the industry standard [iText](https://itextpdf.com/en) library converted to JavaScript. This demo demonstrates how CheerpJ APIs can be used to instance Java objects and call methods directly from JavaScript.

Source: https://cheerpjdemos.leaningtech.com/itextCheerpJDemo.js