---
title: Demos
---

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

## OpenAstexViewer

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

<img src="{{site.baseurl}}/assets/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="{{site.baseurl}}/assets/demo_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="{{site.baseurl}}/assets/demo_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="{{site.baseurl}}/assets/demo_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>