code: public static int transactionFromString(String txIsolation) throws SQLException {
      switch (txIsolation) { //tx_isolation
        case "READ-UNCOMMITTED":
          return Connection.TRANSACTION_READ_UNCOMMITTED;
  
        case "READ-COMMITTED":
          return Connection.TRANSACTION_READ_COMMITTED;
  
        case "REPEATABLE-READ":
          return Connection.TRANSACTION_REPEATABLE_READ;
  
        case "SERIALIZABLE":
          return Connection.TRANSACTION_SERIALIZABLE;
  
        default:
          throw new SQLException("unknown transaction isolation level");
      }
    }
docs: Traduce a String value of transaction isolation to corresponding java value.
  
  @param txIsolation String value
  @return java corresponding value (Connection.TRANSACTION_READ_UNCOMMITTED,
  Connection.TRANSACTION_READ_COMMITTED, Connection.TRANSACTION_REPEATABLE_READ or
  Connection.TRANSACTION_SERIALIZABLE)
  @throws SQLException if String value doesn't correspond to @@tx_isolation/@@transaction_isolation
  possible value