# Has PDF handling changed in 3.7.21?

**URL:** <https://forum.vassalengine.org/t/has-pdf-handling-changed-in-3-7-21/90106>\
**Category:** Technical Support & Bugs\
**Tags:** v3\_7\
**Created:** [May 2, 2026, 4:45pm UTC](https://forum.vassalengine.org/t/has-pdf-handling-changed-in-3-7-21/90106 "2026-05-02T16:45:17Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![cholmcc](https://forum.vassalengine.org/user_avatar/forum.vassalengine.org/cholmcc/32/8319_2.png) [@cholmcc](https://forum.vassalengine.org/u/cholmcc)\
**Post date:** [May 3, 2026, 7:08am UTC](https://forum.vassalengine.org/t/has-pdf-handling-changed-in-3-7-21/90106/11 "2026-05-03T07:08:19Z")

</div>

The relevant code calls [`java.awt.Desktop#browse`](https://docs.oracle.com/javase/8/docs/api/java/awt/Desktop.html#browse-java.net.URI-) _or_ executes - on Windows - `start` - both with an argument of the URI of the PDF to open. Exactly what the URI looks like depends a little on what you are looking at - an embedded PDF or a filesystem PDF.

> [@uckelman](#):
>
> I’m surprised that PDFs ever opened in something other than your browser.

Actually, the docs of the above method says

> Launches the default browser to display a `URI` . If the default browser is not able to handle the specified `URI` , the application registered for handling `URIs` of the specified type is invoked.

so it _should_ work. The relevant OpenJDK code is [here](https://github.com/openjdk/jdk/blame/master/src/java.desktop/windows/classes/sun/awt/windows/WDesktopPeer.java), and the latest commit relevant is [here](https://github.com/openjdk/jdk/commit/eddbd359654cf6e2a437367461231ba37ee76918) which was from the 19th of January, 2026 - and could be part of the 26 release of OpenJDK.

The `browse` handling went from something simple as `open <url>` to a getting the default browser and then opening the URL in that. Arguably that is a regression, and a bug report seems in order.

@mvanleeuwen102 Perhaps you can locate some PDF on your machine - say `C:\Users\you\Desktop\MyTest.pdf` and verify that running

```auto
C:\> start C:\Users\you\Desktop\MyTest.pdf

```

in the `cmd` prompt does indeed open the PDF in Acrobat reader.

Then, next, open your default Web-browser, and type into the location field

```auto
file:C:\Users\you\Desktop\MyTest.pdf

```

and see if it opens the PDF in the browser or Acrobat Reader.

Yours,  
_Christian_

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