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Arpit Agarwal commented on HDFS-6098: ------------------------------------- Correction - modification of the map is not synchronized at all. > ConcurrentModificationException exception during DataNode shutdown > ------------------------------------------------------------------ > > Key: HDFS-6098 > URL: https://issues.apache.org/jira/browse/HDFS-6098 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode > Affects Versions: 2.4.0 > Reporter: Arpit Agarwal > > Exception hit during DN shutdown while running > {{TestWebHdfsWithMultipleNameNodes}}: > {code} > java.util.ConcurrentModificationException: null > at java.util.HashMap$HashIterator.nextEntry(HashMap.java:894) > at java.util.HashMap$EntryIterator.next(HashMap.java:934) > at java.util.HashMap$EntryIterator.next(HashMap.java:932) > at > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl.shutdown(FsVolumeImpl.java:251) > at > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeList.shutdown(FsVolumeList.java:249) > at > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.shutdown(FsDatasetImpl.java:1376) > at > org.apache.hadoop.hdfs.server.datanode.DataNode.shutdown(DataNode.java:1301) > at > org.apache.hadoop.hdfs.MiniDFSCluster.shutdownDataNodes(MiniDFSCluster.java:1523) > at > org.apache.hadoop.hdfs.MiniDFSCluster.shutdown(MiniDFSCluster.java:1498) > at > org.apache.hadoop.hdfs.MiniDFSCluster.shutdown(MiniDFSCluster.java:1482) > at > org.apache.hadoop.hdfs.web.TestWebHdfsWithMultipleNameNodes.shutdownCluster(TestWebHdfsWithMultipleNameNodes.java:99) > {code} -- This message was sent by Atlassian JIRA (v6.2#6252)