Range header support

Fri Apr 25 05:58:37 UTC 2025

Hello Ethan,

This seems to be a reasonable enhancement request. I have filed 
https://bugs.openjdk.org/browse/JDK-8355572 to track this.

Given other priority tasks, this enhancement may not be worked upon 
soon. However, on first sight, this appears to be a reasonably sized 
change isolated to a very specific part of the code. So if you or anyone 
else would like to contribute to this enhancement, please send a message 
to this mailing list (the contribution guide is here 
https://openjdk.org/guide/). I think this enhancement would require a 
bit of experimenting with the code and some back and forth discussions. 
That's OK and can be done here in this mailing list.

-Jaikiran

On 23/04/25 7:53 pm, Ethan McCue wrote:
> I recently encountered a case where it would have been beneficial if 
> jwebserver supported the Range header.
>
> Specifically, there was a learner who made a swing app and wanted to 
> bundle it as an exe or put it on the internet. The path we guided him 
> through was essentially
>
> javac -d compiled --source-path src src/Main.java
> jar --create --file project.jar --main-class Main -C src . -C compiled .
>
> So they had a fully runnable jar. From there it was a bit of a lesson 
> on resources vs. files so that the jar could run self contained, then 
> on to launch4j because it can make the self contained exe they were 
> looking for.
>
> The other thing they wanted was the browser. Looking into the 
> cheerpj - the wasm jvm - it seemed as if we could also get that 
> working pretty easily. Their code was amenable to --release 11 and 
> that's where Cheerpj support currently stops (though they have stated 
> plans to support the latest jdk.)
>
> There were two issues with this. One is either a bug in cheerpj or 
> their app, still investigating. The other is that cheerpj requires 
> support of the Range header on whatever server is serving the jar + 
> html file.
>
> So ideally i would have liked to show them this html and had them run 
> jwebserver to see their jar run in a browser.
>
> <!doctype html>
> <html lang="en">
> <head>
>     <meta charset="utf-8" />
>     <title>CheerpJ test</title>
>     <script src="https://cjrtnc.leaningtech.com/4.0/loader.js"></script>
> </head>
> <body>
> <script>
>     (async function () {
>         await cheerpjInit({version: 11});
>         cheerpjCreateDisplay(800, 600);
>         await cheerpjRunJar("/app/project.jar");
>     })();
> </script>
> </body>
> </html>
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