[Bug] PlantUml local rendering on Ubuntu: java.exe not found

[Mario-Soller]

PlantUML local rendering on Ubuntu: java.exe not found
When trying to build PlantUML files locally during a docfx build using the plantuml.jar on a linux machine, an error gets thrown:

It seems to want to access the java.exe to run the jar.
I tried to run the exact same project on a Windows 10 Machine, where it ran as expected.

To Reproduce
Steps to reproduce the behavior:

1. Install DocFx on an Ubuntu Machine and initialize a project
2. Add a plantUml Diagram to your docfx project
3. Install the plantuml.jar and add to project: https://plantuml.com/de/download (I used MIT)
4. Edit docfx.json:
   
5. Run docfx build

Expected behavior
docfx build should run and build the PlantUML Diagrams using the locally installed plantuml.jar.

Context:

• OS: Ubuntu 24.04.1 LTS
• Docfx version: 2.78.2
• Java version: openjdk 21.0.5 2024-10-15

Additional context
Using the remote server plantuml.com is not possible, due to the machine being offline.

[filzrev]

It seems to be PlantUml.Net side problem.
PlantUml.Net trying to resolve bin/java.exe from JAVA_HOME environment variable.
https://github.com/KevReed/PlantUml.Net/blob/d49cb4cc95b3ab0539d52d2d89421dd8ba7d476b/src/Java/EnvironmentJavaLocator.cs#L18

What's happens when explicitly specify JavaPath option to /usr/lib/jvm/java-21-openjdk-amd64/bin/java? (without .exe)

[Mario-Soller]

Running docfx build using the javaPath in the config causes the process to be stuck indefinetly during this stage:

[filzrev]

Running docfx build using the javaPath in the config causes the process to be stuck indefinetly during this stage:

I'm also confirmed reported issue can be reproduced on Ubuntu OS.
So I've created issue to PlantUml.Net repository. (https://github.com/KevReed/PlantUml.Net/issues/33)

Until problems are fixed by PlantUml.Net side.
There is a workaround by self-hosting plantuml-server on local environment.

[Mario-Soller]

Thank you!
And yes, I am also running a local server (via docker) to workaround this issue.