We have just upgraded our jdk build to 9-ea+149 which has tightened up the accessibility rules. The recommendation seems to be to use the --add-opens flag to override the rules.

I tried export MAVEN_OPTS="--add-opens java.base/java.util=ALL-UNNAMED" which made no difference. Our jdk 9 FAQ does not provided any hints either.

Can anyone provide advice on how to resolve the following maven build error:

[WARNING] Error injecting: org.apache.maven.plugins.war.WarMojo

com.google.inject.ProvisionException: Unable to provision, see the following errors:

1) Error injecting constructor, java.lang.ExceptionInInitializerError

  at org.apache.maven.plugins.war.WarMojo.<init>(Unknown Source)

  while locating org.apache.maven.plugins.war.WarMojo

...

Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field private final java.util.Comparator java.util.TreeMap.comparator accessible: module java.base does not "opens java.util" to unnamed m

odule @669f2128

        at java.base/jdk.internal.reflect.Reflection.throwInaccessibleObjectException(Reflection.java:427)

        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:201)

        at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:171)

        at java.base/java.lang.reflect.Field.setAccessible(Field.java:165)

        at com.thoughtworks.xstream.core.util.Fields.locate(Fields.java:40)

        at com.thoughtworks.xstream.converters.collections.TreeMapConverter.<clinit>(TreeMapConverter.java:50)