@InterfaceAudience.Private
  public void updateConfigurationForQuotasObserver(Configuration conf) {
    // We're configured to not delete quotas on table deletion, so we don't need to add the obs.
    if (
      !conf.getBoolean(MasterQuotasObserver.REMOVE_QUOTA_ON_TABLE_DELETE,
        MasterQuotasObserver.REMOVE_QUOTA_ON_TABLE_DELETE_DEFAULT)
    ) {
      return;
    }
    String[] masterCoprocs = conf.getStrings(CoprocessorHost.MASTER_COPROCESSOR_CONF_KEY);
    final int length = null == masterCoprocs ? 0 : masterCoprocs.length;
    String[] updatedCoprocs = new String[length + 1];
    if (length > 0) {
      System.arraycopy(masterCoprocs, 0, updatedCoprocs, 0, masterCoprocs.length);
    }
    updatedCoprocs[length] = MasterQuotasObserver.class.getName();
    conf.setStrings(CoprocessorHost.MASTER_COPROCESSOR_CONF_KEY, updatedCoprocs);
  }
Adds the {@code MasterQuotasObserver} to the list of configured Master observers to
automatically remove quotas for a table when that table is deleted.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java