Description
Jenkins found this: http://jenkins.thetaphi.de/job/Lucene-Solr-6.x-Linux/1432/
Stack Trace: java.util.ConcurrentModificationException at __randomizedtesting.SeedInfo.seed([FA459DF725097EFF:A77E52876204E1C1]:0) at java.util.HashMap$HashIterator.nextNode(java.base@9-ea/HashMap.java:1489) at java.util.HashMap$KeyIterator.next(java.base@9-ea/HashMap.java:1513) at java.util.AbstractCollection.addAll(java.base@9-ea/AbstractCollection.java:351) at java.util.HashSet.<init>(java.base@9-ea/HashSet.java:119) at org.apache.solr.common.cloud.ZkStateReader.getStateWatchers(ZkStateReader.java:1279) at org.apache.solr.common.cloud.TestCollectionStateWatchers.testSimpleCollectionWatch(TestCollectionStateWatchers.java:116)