Run a Java application
Convert a desktop app to a webapp
CheerpJ can run a Java application in the browser with little to no modifications. This page will help you getting started with CheerpJ and running your first Java application in the browser.
Java source code is not needed to use CheerpJ. If you are building your own application you should already have its
To get started you will need:
- Your Java application file(s). You can also use this TextDemo.jar sample.
- An HTML file where your Java app will be wrapped
- A simple HTTP server to test your webpage locally
1. Create a project directory
Let’s start by creating a project folder where all your files will be. Please copy your java and future HTML files here.
2. Create a basic HTML file
Let’s create a basic HTML file like the following example. Please notice the CheerpJ runtime environment has been integrated and initialized. In this example we are assuming your HTML file and your
.jar files are under the project directory you just created.
Alternatively, if your application is not designed to be executed with the command
java -jar you can replace
cheerpjRunMain() and pass your qualified class name as an argument. For example:
3. Host your page
You can now serve this web page on a simple HTTP server, such as the http-server utility.
Opening the page directly from the disk (for example, by double-clicking on it) is not supported.
What’s going on?
<head>script loads CheerpJ.
cheerpjInitinitialises the CheerpJ runtime environment.
cheerpjCreateDisplaycreates a graphical environment to contain all Java windows.
cheerpjRunJarexecutes your application!
/app/is a virtual filesystem mount point that references the root of the web server this page is loaded from.
You will see the CheerpJ display on your browser with some loading messages before showing your application running. Depending on your application and the optimizations applied, this could take just a few seconds.