Exception in thread "main" java.awt.HeadlessException

[lra]

Hi,

I'm trying to run plantuml on a pristine MacOS 10.15.2 and I'm facing this issue:

$ plantuml
Exception in thread "main" java.awt.HeadlessException
    at java.desktop/java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:165)
    at java.desktop/java.awt.Window.<init>(Window.java:538)
    at java.desktop/java.awt.Frame.<init>(Frame.java:423)
    at java.desktop/javax.swing.JFrame.<init>(JFrame.java:224)
    at net.sourceforge.plantuml.swing.MainWindow2.<init>(MainWindow2.java:159)
    at net.sourceforge.plantuml.Run.main(Run.java:164)

I installed it using homebrew which installed plantuml stable 1.2019.12. The java installed has been installed using homebrew too with brew cask install java:

$ java --version
openjdk 13.0.1 2019-10-15
OpenJDK Runtime Environment (build 13.0.1+9)
OpenJDK 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)

I tried other java versions but am always getting the same error.

Any obvious requirement regarding the java version to install?

Thanks

[junowilderness]

I have the same issue with Oracle Java:

$ java -version
java version "13.0.1" 2019-10-15
Java(TM) SE Runtime Environment (build 13.0.1+9)
Java HotSpot(TM) 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)

[junowilderness]

Have you tried subcommands?

I can process files:

plantuml myfile.puml

I can open the UI:

plantuml -gui

[lra]

Yes subcommands work fine, but calling plantuml without a subcommand throws an exception.

[junowilderness]

Yes, same here.

[raochoar]

Same here...

[moderakh]

same here

[irmiller22]

Just ran into this as well. A little confusing that plantuml invocation throws an exception. Some output about possible commands to run would be helpful.

[arnaudroques]

Right, we are probably going to catch the exception and tell user to go to

• https://forum.plantuml.net/3399/problem-with-x11-and-headless-exception
• https://plantuml.com/en/faq#239d64f675c3e515

[ofloveandhate]

I'm on Ventura, and was unable to run PlantUML on my mac for years because of this error. Neither of those links are useful at all to me.

The thing that got me going this morning was to invoke it with a subcommand --- from above, plantuml -gui provides me the familiary auto-compiling server. (I had been using the online server for the past long while, but it's tiresome and error prone to copy-paste my diagrams back and forth for version control, etc).

My criticism of the two links that show up when calling plantuml without any arguments:

• https://plantuml.com/en/faq#239d64f675c3e515 goes to an FAQ, but adding -Djava.awt.headless=true to the invokation is not helpful; i get the same error message. (my complete invokation was /opt/homebrew/Cellar/openjdk/19.0.2/bin/java -Djava.awt.headless=true -jar /opt/homebrew/Cellar/plantuml/1.2023.2/libexec/plantuml.jar
• https://forum.plantuml.net/3399/problem-with-x11-and-headless-exception is a forum post from 2015 about X11, which is, AFAIK, dead on MacOS.

IMO, it would be better to just tell the user to call plantuml with -gui if they want the server, and other arguments if one-shot compiling diagrams.

[arnaudroques]

IMO, it would be better to just tell the user to call plantuml with -gui if they want the server, and other arguments if one-shot compiling diagrams.

It would be nice if you could update the faq yourself. It's just easy as clicking on "edit this part".

Since we don't have any Mac, we do know even know what we are talking about :-)

Thanks for your help!

[charlieblevins]

I had the same experience on Ventura. I've updated the docs as suggested.

[Blaisorblade]

Thank you @charlieblevins — I tried to make that info more prominent since I struggled to find it.