code: private void rethrow(Connection conn, SQLException cause, String sql, Object... params)
              throws MjdbcSQLException {
  
          MjdbcSQLException ex = this.exceptionHandler.convert(conn, cause, sql, params);
  
          throw ex;
      }
docs: Throws a new exception with a more informative error message.
  
  @param conn   SQL Connection which is used in current session. Is not guaranteed to be open
  @param cause  The original exception that will be chained to the new
  exception when it's rethrown.
  @param sql    The query that was executing when the exception happened.
  @param params The query replacement parameters; <code>null</code> is a valid
  value to pass in.
  @throws SQLException if a database access error occurs