FULL PRODUCT VERSION :
jdk-9-ea+168_linux-x64

ADDITIONAL OS VERSION INFORMATION :
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty (Linux 4.4.0-45-generic)

EXTRA RELEVANT SYSTEM CONFIGURATION :
Travis configuration copied from https://travis-ci.org/junit-team/junit5/jobs/232398716/config

{
  "language": "java",
  "sudo": false,
  "dist": "trusty",
  "install": [
    "cd ..",
    "wget http://download.java.net/java/jdk9/archive/168/binaries/jdk-9-ea+168_linux-x64_bin.tar.gz",
    "tar -xzf jdk-9-ea+168_linux-x64_bin.tar.gz",
    "export JAVA_HOME=$PWD/jdk-9",
    "PATH=$JAVA_HOME/bin:$PATH",
    "cd -"
  ],
  "script": [
    "./gradlew check --scan"
  ],
  "group": "stable",
  "env": "JDK_JAVA_OPTIONS='--permit-illegal-access'",
  "jdk": "oraclejdk9",
  "os": "linux"
}

A DESCRIPTION OF THE PROBLEM :
While building JUnit 5 on Travis CI using jdk-9-b168 on branch [1] I used the "kill switch" to allow Gradle/Groovy perform their work with illegal accesses allowed. The build failed due to an OutOfMemoryException. See [2] for the logs.

When I replace the "kill switch" with "--add-opens" options, the build runs. See [3] for details.


[1] https://github.com/junit-team/junit5/pull/842/commits
[2] https://travis-ci.org/junit-team/junit5/jobs/232398716#L947
[3] https://travis-ci.org/junit-team/junit5/jobs/232406998

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Clone master branch https://github.com/junit-team/junit5 and replace all "--add-opens" options with the single "--permit-illegal-access". Commit, push and wait for Travis to pick up the cloned branch.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The build should run and terminate without an error.
ACTUAL -
The build crashes with error:
  "Process 'Gradle Test Executor 2' finished with non-zero exit value 137"

http://stackoverflow.com/questions/38967991/why-are-my-gradle-builds-dying-with-exit-code-137

ERROR MESSAGES/STACK TRACES THAT OCCUR :
https://travis-ci.org/junit-team/junit5/jobs/232398716#L947

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
.travis.yml from

language: java
sudo: false
dist: trusty

matrix:
  include:
    - jdk: oraclejdk8
      addons: {apt: {packages: [oracle-java8-installer]}}
    - jdk: oraclejdk9
      install:
        - cd ..
        - wget http://download.java.net/java/jdk9/archive/168/binaries/jdk-9-ea+168_linux-x64_bin.tar.gz
        - tar -xzf jdk-9-ea+168_linux-x64_bin.tar.gz
        - export JAVA_HOME=$PWD/jdk-9
        - PATH=$JAVA_HOME/bin:$PATH
        - cd -
        - ./gradlew -version
      env: JDK_JAVA_OPTIONS='--add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED'
           #JDK_JAVA_OPTIONS='--permit-illegal-access' # PRODUCES EXIT VALUE 137 !!!

# Display Gradle version instead of letting Travis execute './gradlew assemble' by default
install:
  - ./gradlew -version

script:
  - ./gradlew check --scan
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use:

  JDK_JAVA_OPTIONS='--add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED'

instead of:

  JDK_JAVA_OPTIONS='--permit-illegal-access'