Statement sta = con.createStatement();
ResultSet rst = sta.executeQuery("select * from book");

Statement sta = con.createStatement("select * from book");
ResultSet rst = sta.executeQuery();

PreparedStatement pst = con.prepareStatement();
ResultSet rst = pst.executeQuery("select * from book");

PreparedStatement pst = con.prepareStatement("select * from book");
ResultSet rst = pst.executeQuery();