Build failed in Jenkins: java-metadata-aggregator-0.10-multi » JDK-1.9,master #652

[Shibboleth Jenkins]

See <https://build.shibboleth.net/jenkins/job/java-metadata-aggregator-0.10-multi/jdk=JDK-1.9,label=master/652/display/redirect>

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Started by upstream project "java-metadata-aggregator-0.10-multi" build number 652
originally caused by:
 Started by timer
Building on master in workspace <https://build.shibboleth.net/jenkins/job/java-metadata-aggregator-0.10-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/java-metadata-aggregator # timeout=10
Fetching upstream changes from git://git.shibboleth.net/java-metadata-aggregator
 > git --version # timeout=10
 > git fetch --tags --progress git://git.shibboleth.net/java-metadata-aggregator +refs/heads/*:refs/remotes/origin/*
Checking out Revision 16250af9bdb46c9fd27f92616a08a8ef62e50152 (refs/remotes/origin/master)
 > git config core.sparsecheckout # timeout=10
 > git checkout -f 16250af9bdb46c9fd27f92616a08a8ef62e50152
Commit message: "MDA-195 - fix types for Java 9 compatibility"
 > git rev-list 16250af9bdb46c9fd27f92616a08a8ef62e50152 # timeout=10
[master] $ /opt/maven/bin/mvn -f aggregator-parent/pom.xml -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.
testng-results.xml was last modified before this build started. Ignoring it.
testng-results.xml was last modified before this build started. Ignoring it.
Saving reports...
Found matching files but did not find any TestNG results.