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Stéphane Tréboux
Asked: 2018-10-27 07:52:00 +0800 CST

MediathekView does not start in Kubuntu 18.10 (cosmic)

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In Kubuntu 18.10 (cosmic) the application MediathekView crashes with the following error message:

java.lang.NoClassDefFoundError: com/jidesoft/utils/ThreadCheckingRepaintManager

Remark: the message is only visible when MediathekView is started from a console using the command mediathekview. When MediathekView is started from the launcher nothing happens (no error message, no nothing).

kubuntu java jar 18.10

5 Answers

  1. This issue does not exist with full versions of MediathekView which can be downloaded from the official website here; this version comes with the missing libraries inside a lib folder; version 13.2.1, the latest at the time of this answer worked well for me. The installation only consists of unpacking the archive. The file MediathekView.jar starts the application, the lib folder is required for the application to start.

    Starting MediathekView using the command java -jar MediathekView.jar will not work though; this new error is thrown:

    Exception in thread "main" java.lang.NoClassDefFoundError: javafx/concurrent/Task

    For some reason JavaFX is not found. First you must make sure that the package libopenjfx-java is installed; since it is a dependency of MediathekView it should be already installed. Then all the JAR files for JavaFX must be added by hand to the class path when starting MediathekView:

    java -cp MediathekView.jar:/usr/share/java/javafx-base-11.jar:/usr/share/java/javafx-controls-11.jar:/usr/share/java/javafx-fxml-11.jar:/usr/share/java/javafx-graphics-11.jar:/usr/share/java/javafx-media-11.jar:/usr/share/java/javafx-swing-11.jar:/usr/share/java/javafx-web-11.jar mediathek.Main

    You can add a path in front of MediathekView.jar to match the location where you unpacked the installation package.

    MediathekView should start, the splash screen will not work though.

    And MediathekView has a picky Java version check built in and will complain about with some specific JDK release numbers; for instance OpenJDK 11 will work but not the bug fixed version OpenJDK 11.0.1.

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  2. You can just copy the following line:

    java -cp MediathekView.jar:/usr/share/java/javafx-base-11.jar:/usr/share/java/javafx-controls-11.jar:/usr/share/java/javafx-fxml-11.jar:/usr/share/java/javafx-graphics-11.jar:/usr/share/java/javafx-media-11.jar:/usr/share/java/javafx-swing-11.jar:/usr/share/java/javafx-web-11.jar mediathek.Main

    in the file mediathekview.sh.
    Put it in the first line after the comments, then it will work if you run mediathekview.sh.

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  3. Best Answer

    You can remove MediathekView and use MediathekViewWeb instead. It has less features (see the readme, German only) but it does not require any installation.

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  4. No, you can't "just copy that line". If you do, you'll receive the very next error:

    Exception in thread "main" java.lang.UnsupportedClassVersionError:   
javafx/concurrent/Task has been compiled by a more recent version of the Java Runtime  
(class file version 54.0),  
this version of the Java Runtime only recognizes class file versions up to 52.0 –

    because the libs lead to classes compiled by JDK11, and not JDK8.

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  5. Check version of openjfx ("sudo apt install openjfx" installs it or returns the version). I am on 18.04 LTS. So it was 1.8.xx. Concerning java I have several versions installed. When not the corresponding version is chosen (8) this error was reported. To switch versions use "sudo update-alternatives --config java" which indicates which versions are installed, which is chosen and which number you have to insert to switch. To recheck you can enter "java --version".

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