@Test
  public void testSlowLogResponses() throws Exception {
    // get all live server names
    Collection<ServerName> serverNames = ADMIN.getRegionServers();
    List<ServerName> serverNameList = new ArrayList<>(serverNames);

    // clean up slowlog responses maintained in memory by RegionServers
    List<Boolean> areSlowLogsCleared = ADMIN.clearSlowLogResponses(new HashSet<>(serverNameList));

    int countFailedClearSlowResponse = 0;
    for (Boolean isSlowLogCleared : areSlowLogsCleared) {
      if (!isSlowLogCleared) {
        ++countFailedClearSlowResponse;
      }
    }
    Assert.assertEquals(countFailedClearSlowResponse, 0);

    List<LogEntry> onlineLogRecords = ADMIN.getLogEntries(new HashSet<>(serverNames), "SLOW_LOG",
      ServerType.REGION_SERVER, 100, null);
    // after cleanup of slowlog responses, total count of slowlog payloads should be 0
    Assert.assertEquals(onlineLogRecords.size(), 0);
    List<LogEntry> balancerDecisionRecords =
      ADMIN.getLogEntries(null, "BALANCER_DECISION", ServerType.MASTER, 100, null);
    Assert.assertEquals(balancerDecisionRecords.size(), 0);
  }
Do get of RegionInfo from Master using encoded region name.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAdmin2.java