HDFS-9134, it has moved the LEASE_SOFTLIMIT_PERIOD,LEASE_HARDLIMIT_PERIOD constants from HdfsServerConstants to HdfsConstants because these two constants are used by DFSClient which is moved to hadoop-hdfs-client. And constants in HdfsConstants can be both used by client and server side. In addition, I have checked that these two constants in HdfsServerConstants has already not been used in project now and were all replaced by HdfsConstants.LEASE_SOFTLIMIT_PERIOD,HdfsConstants.LEASE_HARDLIMIT_PERIOD. So I think we can remove these unused constant values in HdfsServerConstants completely. Instead of we can use them in HdfsConstants if we want to use them in the future.