private void createSystemTable(Admin admin, TableDescriptor descriptor) throws IOException {
    try {
      admin.createTable(descriptor);
    } catch (TableExistsException e) {
      // swallow because this class is initialized in concurrent environments (i.e. bulkloads),
      // so may be subject to race conditions where one caller succeeds in creating the
      // table and others fail because it now exists
      LOG.debug("Table {} already exists, ignoring", descriptor.getTableName(), e);
    }
  }
Connection to HBase cluster, shared among all instances
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java