JRE (Java Runtime Environment) in version 1.8 of higher must be installed. To check the version of the installed JRE, use following command:
java -version
Predictor Factory is using JavaFX present in Oracle's JRE. If a non-Oracle JRE is installed (commonly OpenJDK, the default JRE on Ubuntu), the support for JavaFX has to be installed separately:
sudo apt-get install openjfx