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:~$