package jython-stilts 3.1.2-2 failed to install/upgrade: installed jython-stilts package post-installation script subprocess returned error exit status 1

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

I can't reproduce this.

What I did:

 * created a Ubuntu 18.04 chroot, and did a schroot into it
 * added "multiverse universe" to `/etc/apt/sources.list`
 * `apt update`
 * `apt install jython-stilts`

I get warnings, which are created by the startup of Jython:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by jnr.posix.JavaLibCHelper$ReflectiveAccess (file:/usr/share/java/jnr-posix.jar) to method sun.nio.ch.SelChImpl.getFD()
WARNING: Please consider reporting this to the maintainers of jnr.posix.JavaLibCHelper$ReflectiveAccess
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

But the package installs fine, and a quick test afterwards shows that it imports fine:

(bionic)oles@donar:~$ jython
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by jnr.posix.JavaLibCHelper$ReflectiveAccess (file:/usr/share/java/jnr-posix.jar) to method sun.nio.ch.SelChImpl.getFD()
WARNING: Please consider reporting this to the maintainers of jnr.posix.JavaLibCHelper$ReflectiveAccess
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Jython 2.7.1 (, Oct 22 2017, 13:43:00)
[OpenJDK 64-Bit Server VM (Oracle Corporation)] on java10.0.1
Type "help", "copyright", "credits" or "license" for more information.
>>> import stilts
>>>

The difference is that in the log above, there is a package "ibm-java80-jdk" installed, which however is not part of Ubuntu 18.04.

From the terminal log:

Exception in thread "main" java.lang.NoSuchMethodError: java/nio/ByteBuffer.limit(I)Ljava/nio/ByteBuffer; (loaded from /usr/lib/jvm/java-ibm-x86_64-80/jre/lib/rt.jar by <Bootstrap Loader>) called from class jline.internal.InputStreamReader (loaded from file:/usr/share/java/jline2.jar by sun.misc.Launcher$AppClassLoader@4b7a0fb9).
 at jline.internal.InputStreamReader.<init>(InputStreamReader.java:104)
 at jline.console.ConsoleReader.setInput(ConsoleReader.java:330)
 at jline.console.ConsoleReader.<init>(ConsoleReader.java:248)
 at org.python.util.JLineConsole.install(JLineConsole.java:107)
 at org.python.core.Py.installConsole(Py.java:1744)
 at org.python.core.PySystemState.initConsole(PySystemState.java:1258)
 at org.python.core.PySystemState.doInitialize(PySystemState.java:1109)
 at org.python.core.PySystemState.initialize(PySystemState.java:1023)
 at org.python.core.PySystemState.initialize(PySystemState.java:979)
 at org.python.core.PySystemState.initialize(PySystemState.java:974)
 at org.python.util.jython.run(jython.java:263)
 at org.python.util.jython.main(jython.java:142)

I would also assume that the bug is not in jython-stilts, but in jython itself. Could anyone just install jython (with the ibm-java80-jdk), and then just start "jython"?