I installed OpenJDK-11 as described here. I ran sudo apt install openjfx

My java version:

$ java -version
openjdk version "11.0.3" 2019-04-16
OpenJDK Runtime Environment (build 11.0.3+7-Ubuntu-1ubuntu1)
OpenJDK 64-Bit Server VM (build 11.0.3+7-Ubuntu-1ubuntu1, mixed mode, sharing)

But still I get ava.lang.NoClassDefFoundError: javafx/application/Application which indicates that the jre cannot find the FX classes.


You are getting this error because your runtime PATH to javafx is probably incorrect or missing.

Please, follow these steps:

Check the path of JavaFX. (example: /usr/share/openjfx/lib/)

Then run command:

java --module-path $FX-PATH --add-modules javafx.controls -jar sample.jar

where $FX-PATH should be set or replaced with mentioned JavaFX path.

If you need to add more modules, you can specify them in --add-modules parameter.
(--add-modules javafx.controls,javafx.fxml)

  • 2
    You might need to add more FX modules to command to be able to run w/out errors, e.g. --add-modules javafx.controls,javafx.fxml,javafx.graphics. You can see list of available modules as far as I can tell from structure of legal folder of downloaded javafx-sdk. Jan 14 '20 at 2:56

Java FX is no longer packaged with the Java runtime. You must download and package the Jar with JavaFX runtime, see https://openjfx.io/openjfx-docs/ in order to learn how best to get this up and running.


I recommend you to go with https://openjfx.io/openjfx-docs/ .i am using Eclipse IDE but it works for all IDE

Then you can refer to this global variable when setting the VM options as:

In IDE Right-click on project->Run As -> Run Configuration ->Arguments->VM Arguments

For Windows,

--module-path "\path to javafx\lib" --add-modules javafx.controls,javafx.fxml

For Linux,

--module-path /path to javafx/lib --add-modules javafx.controls,javafx.fxml

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