Leaning Technologies

The home of WebVM, Browserpod, Cheerp, CheerpJ, and CheerpX. Chat about virtual machines, compilers, and WebAssembly!

Leaning Technologies

The home of WebVM, Browserpod, Cheerp, CheerpJ, and CheerpX. Chat about virtual machines, compilers, and WebAssembly!

6/7/2025

OffscreenCanvas

After not finding 'OffscreenCanvas' amongst the Cheerp 3.0 c++ include files, I had posted an 'issue' about it on github, to be told that I should check here (though in searching here, I only see two nebulous mentions which don't indicate availability), and that it could be obtained by downloading the latest sources & recompiling (however, in performing a ~naïve github search of the sources therein, I have not yet found 'OffscreenCanvas' defined there either!?). The other suggestion was 'nightl...

ozkan

5/30/2025

I am trying to run my javaFX app in cheerpj, and tried this html in windows

Here is my project https://github.com/ozkanpakdil/swaggerific only complexity is javafx in the project, probably I should provide javafx lib path to cheerpj but I could not find a way to do it, what should I do ? ``` <!doctype html> <html lang="en"> <head>...

Ch K Balaji Mirthipati

5/27/2025

Problem with CheerJ applet runner

Problem with CheerJ applet runner in my Chrome, when I enable it, it automatically turning off, so I have to enable it again and again and again...

Ch K Balaji Mirthipati

5/23/2025

Is there a Firefox add-on for CheerpJ?

Need to run a Java applet for a legacy website. I can use Chrome, but can't use Chrome Web Store

JeffPawn64

5/22/2025

Java App Cannot Find Files Through CheerpJ Virtual Filesystem

Hi, I have a Java application that I'm trying to run in the context of CheerpJ. The application reads image files from a relative path called "res/someimage.png". The app runs fine locally; the images load. I followed Alessandro's advice to use the absolute path "/files" virtual filesystem. Now, my Java app tries to access "/files/res/someimage.png". In my web server root, I have a subdirectory "res", which contains the various images. My .jar is in my server root. However, within the Che...

JacobDK123

4/29/2025

UnsupportedClassVersionError

Explcitly running with java 11, but sometimes on page refresh/app launch get this. ususally if I refresh again, the error is gone. But seems quite strange, since the class in question is a Java library class. In this case it is the BasicLookAndFeel class, but sometimes it is other JRE classes: java.lang.UnsupportedClassVersionError: Required Java version 45532, but CheerpJ only supports up to Java 11 at this time. Unsupported class: javax/swing/plaf/basic/BasicLookAndFeel...

JacobDK123

4/29/2025

cacerts No such file or directory

Expected to find the JRE trusted certs at, but got: Caused by: java.io.FileNotFoundException: /lt/11/lib/security/cacerts (No such file or directory)...

JacobDK123

4/29/2025

java.lang.UnsatisfiedLinkError 2

##4 Caused by: java.lang.UnsatisfiedLinkError: Java_java_io_ObjectStreamClass_initNative at java.io.ObjectStreamClass.<clinit>(Unknown Source) ~[na:na] at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source) ~[na:na] at java.io.ObjectInputStream.readClassDesc(Unknown Source) ~[na:na]...

JacobDK123

4/29/2025

UnsatisfiedLinkError

Great with Java 11 suuport. I immediateliy tried our old desktop app, but quickly ran into these problems with the bundled java libraries. Am I doing somethin wrong, or is this simply corners of the JRE not addressed yet? Here's the stack traces: #1 Caused by: java.lang.UnsatisfiedLinkError: no management_ext in java.library.path: [.]...

SharkBaitDLS

4/27/2025

Licensing Confusion

I'm struggling to understand the licensing model a bit. I'm working on a FOSS project that has more contributors than just myself -- does that mean we're ineligible for the community license? Would that put us under the non-profit organization bucket?

User

4/23/2025

Why isn't the .jar file reading for the web test?

im a complete noob at this so tell me everything im doing wrong

oyin.bo

4/21/2025

VSCode extension

I want to build a VSCode extension running Linux+bash in WASM usig this CheerpX library. * Do I need a license? * Do I need any caveats in my extension Readme? My goal is to enable VSCode/web to run more development tasks in browser, without full local VSCode. Hopefully enabling software development at lower footprint, and using tablets and hand-held devices....

parvob19

3/17/2025

adding a file as a jar argument cheerpjRunJar

I have a jar file that asks for a config file as an argument as follows: example.jar --config /path/to/config.json It seems as if the applet cannot get access to this file. I have it in the same directory as the .jar file, and have tried adding the arg per cheerpj documentation: await cheerpjRunJar("/app/2009scape.jar", ["--config /app/config.json"]); am I missing something, or is adding external files a browser security issue that will not be easily solved?...

TimBarron

2/25/2025

Interacting with System.in

I'm looking into using CheerpJ to put together a website to showcase student projects in my intro programming class. I've been testing with projects from past semesters. Many are using swing and are working well, but some students' projects have user interaction in the terminal (REPL style). When I run non-gui applications I see stdout in the browser console which is a good start, but I'm not sure how to interact with stdin.

SS Zeklord

2/15/2025

I cannot get the example applet to work in my chrome browser on mac os

I tried cloning the example here - https://github.com/leaningtech/cheerpj-meta/tree/main/examples/Pitch-Applet But am not able to get it to run...

pescennius

2/10/2025

multiprocessing

Can I leverage my systems other cores via webvm or am I limited to single core execution?

pescennius

2/6/2025

webvm filesystem and headless

I was directed to Discord to learn more about using webvm with filesystem APIs. I hope this is the right place to ask. I want to run webvm headless, such that my Javascript executes shell commands but I display my own html/js frong end. I also want to be able to save files to the filesystem or at least as a stopgap serialize those files generated in my VM to Javascript to enable file downloads.

Stitch

2/6/2025

have a running Terminal on my website

Hello, guys if anyone could help me please I am trying to use Cheerpx to have a running Terminal on my website, I cant figure out a way to do it im using JS and html for now and im currently stuck I do not know how to set it up. The image above is what I have ofc there isnt an actual terminal,...

The Think Tank

2/6/2025

cheerpJ usage patterns..?

The application does not launch, normally you should access another page. This is just the loading page

Axx

2/3/2025

Compatibility ?

I have a community card playground, quite old (developed more than 10 years ago). It works via JAVA applets. This playground is multiplayer. I tried the browser plugin, it doesn't work.

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Leaning Technologies

The home of WebVM, Browserpod, Cheerp, CheerpJ, and CheerpX. Chat about virtual machines, compilers, and WebAssembly!

Leaning Technologies

The home of WebVM, Browserpod, Cheerp, CheerpJ, and CheerpX. Chat about virtual machines, compilers, and WebAssembly!