public String getDelegationToken(String owner, String renewer) throws SQLException {
    if (isClosed) {
      throw new SQLException("Connection is closed");
    }
    TGetDelegationTokenReq req = new TGetDelegationTokenReq(sessHandle, owner, renewer);
    try {
      TGetDelegationTokenResp tokenResp = client.GetDelegationToken(req);
      Utils.verifySuccess(tokenResp.getStatus());
      return tokenResp.getDelegationToken();
    } catch (TException e) {
      throw new SQLException("Could not retrieve token: " +
          e.getMessage(), " 08S01", e);
    }
  }
Lookup varName in sessConfMap, if its null or empty return the default
value varDefault
@param varName
@param varDefault
@return
jdbc/src/java/org/apache/hive/jdbc/HiveConnection.java