gradle: "illegal reflective access" with openjdk-9

[Andreas Schildbach]

Since a couple of days, gradle doesn't work on Ubuntu 18.04 LTS any more on openjdk8. Installing openjdk9 kind of works around this problem, but it throws a couple of scary illegal access warnings instead. Just a days ago, everything worked fine so there must have been some bug introduced into a dependent package.

$ gradle -S
Starting a Gradle Daemon, 8 busy and 2 incompatible and 1 stopped Daemons could not be reused, use --status for details

FAILURE: Build failed with an exception.

* What went wrong:
java.nio.ByteBuffer.limit(I)Ljava/nio/ByteBuffer;

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
java.lang.NoSuchMethodError: java.nio.ByteBuffer.limit(I)Ljava/nio/ByteBuffer;
        at org.gradle.internal.remote.internal.inet.SocketConnection$SocketInputStream.<init>(SocketConnection.java:154)
        at org.gradle.internal.remote.internal.inet.SocketConnection.<init>(SocketConnection.java:59)
        at org.gradle.internal.remote.internal.inet.SocketConnectCompletion.create(SocketConnectCompletion.java:39)
        at org.gradle.launcher.daemon.client.DefaultDaemonConnector.connectToDaemon(DefaultDaemonConnector.java:255)
        at org.gradle.launcher.daemon.client.DefaultDaemonConnector.connectToDaemonWithId(DefaultDaemonConnector.java:241)
        at org.gradle.launcher.daemon.client.DefaultDaemonConnector.startDaemon(DefaultDaemonConnector.java:213)
        at org.gradle.launcher.daemon.client.DefaultDaemonConnector.connect(DefaultDaemonConnector.java:130)
        at org.gradle.launcher.daemon.client.DaemonClient.execute(DaemonClient.java:127)
        at org.gradle.launcher.daemon.client.DaemonClient.execute(DaemonClient.java:81)
        at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:51)
        at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:173)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:244)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:217)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:33)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:210)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:174)
        at org.gradle.launcher.Main.doAction(Main.java:33)
        at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:60)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:37)
        at org.gradle.launcher.GradleMain.main(GradleMain.java:23)

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gradle 3.4.1-4
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
ApportVersion: 2.20.9-0ubuntu2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Apr 1 00:04:40 2018
InstallationDate: Installed on 2013-01-11 (1905 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gradle
UpgradeStatus: Upgraded to bionic on 2018-03-07 (24 days ago)

[Andreas Schildbach (schildbach)]

I think the issue that Gradle has been updated to the Debian experimental version 3.4.1. Before, it was synched to "unstable" 3.2.1.

[Steve Langasek (vorlon)]

openjdk-8 will not be supported in 18.04, as discussed in <https://lists.ubuntu.com/archives/ubuntu-release/2018-February/004275.html>, <https://lists.ubuntu.com/archives/ubuntu-release/2018-March/004359.html>. The java-common package points to openjdk-9 today, and while openjdk-8 will be retained in universe for 18.04 for compatibility, there is no committment that any other particular package will remain compatible with openjdk-8.

What are the "scary illegal access warnings" that you see with openjdk-9?

[Andreas Schildbach (schildbach)]

Thanks Steve for the clarification. I personally feel the (forced) move to Java9 comes too early, as I
just have moved my Android projects to Java8 with quite some headache. But I guess I have to adapt.

Here is the output of gradle under openjdk-9. The first 5 lines are always the same regardless of the parameters.

$ gradle
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.gradle.internal.reflect.JavaMethod (file:/usr/share/gradle/lib/gradle-base-services-3.4.1.jar) to method java.lang.ClassLoader.getPackages()
WARNING: Please consider reporting this to the maintainers of org.gradle.internal.reflect.JavaMethod
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
:help

Welcome to Gradle 3.4.1.

To run a build, run gradle <task> ...

To see a list of available tasks, run gradle tasks

To see a list of command-line options, run gradle --help

To see more detail about a task, run gradle help --task <task>

BUILD SUCCESSFUL

Total time: 1.105 secs

[Steve Langasek (vorlon)]

Thanks. That definitely looks like something we should be fixing for 18.04.

[Launchpad Janitor (janitor)]

This bug was fixed in the package gradle - 3.4.1-6

---------------
gradle (3.4.1-6) unstable; urgency=medium

  * Team upload.
  * Improved the Java 8 compatibility patch

 -- Emmanuel Bourg <email address hidden> Thu, 05 Apr 2018 08:39:52 +0200