code: @Override
      public PoolablePreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
          return new PoolablePreparedStatement(internalConn.prepareStatement(sql, columnNames), this, null);
      }
docs: Method prepareStatement.
  
  @param sql
  @param columnNames
  @return PreparedStatement
  @throws SQLException
  @see java.sql.Connection#prepareStatement(String, String[])