Comment 4 for bug 1793852

Still actual for freshly upgraded 18.04 LTS. All output is below:

mate@bionic:~$ sikulix
[error] RunTimeINIT: Java version not detected (using 7): 10.0.2+13-Ubuntu-1ubuntu0.18.04.3
java ?7?-64 version 10.0.2+13-Ubuntu-1ubuntu0.18.04.3 vm 10.0.2+13-Ubuntu-1ubuntu0.18.04.3 class 54.0 arch amd64
*** system properties dump
awt.toolkit = sun.awt.X11.XToolkit
file.encoding = UTF-8
file.encoding.pkg = sun.io
file.separator = /
java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment
java.awt.printerjob = sun.print.PSPrinterJob
java.class.path = /usr/share/sikulix/sikulix.jar
java.class.version = 54.0
java.home = /usr/lib/jvm/java-11-openjdk-amd64
java.io.tmpdir = /tmp
java.library.path = /usr/lib/jni:/usr/lib/arm-linux-gnueabi/jni:/usr/lib/arm-linux-gnueabihf/jni:/usr/lib/i386-gnu/jni:/usr/lib/i386-linux-gnu/jni:/usr/lib/i386-kfreebsd-gnu/jni:/usr/lib/mips-linux-gnu/jni:/usr/lib/mipsel-linux-gnu/jni:/usr/lib/powerpc-linux-gnu/jni:/usr/lib/powerpc-linux-gnuspe/jni:/usr/lib/sparc-linux-gnu/jni:/usr/lib/x86_64-linux-gnux32/jni:/usr/lib/hppa-linux-gnu/jni:/usr/lib/sh4-linux-gnu/jni:/usr/lib/m68k-linux-gnu/jni
java.runtime.name = OpenJDK Runtime Environment
java.runtime.version = 10.0.2+13-Ubuntu-1ubuntu0.18.04.3
java.specification.name = Java Platform API Specification
java.specification.vendor = Oracle Corporation
java.specification.version = 10
java.vendor = Oracle Corporation
java.vendor.url = http://java.oracle.com/
java.vendor.url.bug = http://bugreport.java.com/bugreport/
java.version = 10.0.2
java.version.date = 2018-07-17
java.vm.compressedOopsMode = 32-bit
java.vm.info = mixed mode
java.vm.name = OpenJDK 64-Bit Server VM
java.vm.specification.name = Java Virtual Machine Specification
java.vm.specification.vendor = Oracle Corporation
java.vm.specification.version = 10
java.vm.vendor = Oracle Corporation
java.vm.version = 10.0.2+13-Ubuntu-1ubuntu0.18.04.3
jdk.debug = release
line.separator =

os.arch = amd64
os.name = Linux
os.version = 4.15.0-39-generic
path.separator = :
python.home = /usr/share/jython
sikuli.console = true
sun.arch.data.model = 64
sun.boot.library.path = /usr/lib/jvm/java-11-openjdk-amd64/lib
sun.cpu.endian = little
sun.cpu.isalist =
sun.font.fontmanager = sun.awt.X11FontManager
sun.io.unicode.encoding = UnicodeLittle
sun.java.command = /usr/share/sikulix/sikulix.jar
sun.java.launcher = SUN_STANDARD
sun.jnu.encoding = UTF-8
sun.management.compiler = HotSpot 64-Bit Tiered Compilers
sun.os.patch.level = unknown
user.country = US
user.dir = /home/mate
user.home = /home/mate
user.language = en
user.name = mate
user.timezone = Europe/Moscow
*** system properties dump end
[info] runcmd: lsb_release -i -r -s
Exception in thread "main" java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader
 at org.sikuli.script.RunTime.storeClassPath(RunTime.java:2505)
 at org.sikuli.script.RunTime.isOnClasspath(RunTime.java:2552)
 at org.sikuli.script.RunTime.isJarOnClasspath(RunTime.java:2576)
 at org.sikuli.script.RunTime.libsExport(RunTime.java:933)
 at org.sikuli.script.RunTime.init(RunTime.java:720)
 at org.sikuli.script.RunTime.get(RunTime.java:297)
 at org.sikuli.ide.SikuliIDE.run(SikuliIDE.java:232)
 at org.sikuli.ide.Sikulix.main(Sikulix.java:31)
mate@bionic:~$ update-java-alternatives -l
java-1.11.0-openjdk-amd64 1101 /usr/lib/jvm/java-1.11.0-openjdk-amd64
mate@bionic:~$