pdfsam crashes immediately at startup

[Raphael Manfredi]

$ pdfsam
Exception in thread "main" java.lang.NoClassDefFoundError: javafx/scene/layout/HBox
        at java.base/java.lang.ClassLoader.defineClass1(Native Method)
        at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1009)
        at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
        at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:802)
        at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:700)
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:623)
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
        at org.pdfsam.community.App.main(App.java:34)
Caused by: java.lang.ClassNotFoundException: javafx.scene.layout.HBox
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
        ... 10 more

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: pdfsam 3.3.5-1
ProcVersionSignature: Ubuntu 4.15.0-43.46-generic 4.15.18
Uname: Linux 4.15.0-43-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Jan 7 18:40:41 2019
InstallationDate: Installed on 2018-06-29 (191 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
SourcePackage: pdfsam
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.