Build failed in Jenkins: spring-extensions-v6-multi » JDK-1.9,master #33

[Shibboleth Jenkins]

See <https://build.shibboleth.net/jenkins/job/spring-extensions-v6-multi/jdk=JDK-1.9,label=master/33/display/redirect>

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Started by upstream project "spring-extensions-v6-multi" build number 33
originally caused by:
 Started by timer
Building on master in workspace <https://build.shibboleth.net/jenkins/job/spring-extensions-v6-multi/jdk=JDK-1.9,label=master/ws/>
 > git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from the remote Git repository
 > git config remote.origin.url git://git.shibboleth.net/spring-extensions # timeout=10
Fetching upstream changes from git://git.shibboleth.net/spring-extensions
 > git --version # timeout=10
 > git fetch --tags --progress git://git.shibboleth.net/spring-extensions +refs/heads/*:refs/remotes/origin/*
Checking out Revision 90a6110dc5a64257e320726aa36f33ba4fbba8bd (refs/remotes/origin/master)
 > git config core.sparsecheckout # timeout=10
 > git checkout -f 90a6110dc5a64257e320726aa36f33ba4fbba8bd
Commit message: "Javadoc fixes"
 > git rev-list 90a6110dc5a64257e320726aa36f33ba4fbba8bd # timeout=10
[master] $ /opt/maven/bin/mvn -Djdk=JDK-1.9 -Dmatrix-combinations= -Dlabel=master clean test -Prelease --update-snapshots --fail-at-end
Error: JAVA_HOME is not defined correctly.
  We cannot execute /opt/java9/bin/java
Build step 'Invoke top-level Maven targets' marked build as failure
TestNG Reports Processing: START
Looking for TestNG results report in workspace using pattern: **/target/surefire-reports/testng-results.xml
testng-results.xml was last modified before this build started. Ignoring it.
Saving reports...
Found matching files but did not find any TestNG results.