Connection con = null;
        try {
            Class.forName("org.postgresql.Driver");
            con = DriverManager.getConnection("jdbc:postgresql://127.0.0.1:5432/", "kyz", "rahasia");
        } catch (Exception e) {
            System.err.println(e);
            System.exit(0);
        }
        PreparedStatement pst = null;
        ResultSet rs = null;
        if (con != null) {
            try {
                pst = con.prepareStatement("SELECT columnfoo FROM mytable WHERE columnfoo = ?");
                pst.setString(1, "test2");
                //pst.setInt(1, 21314);
                rs = pst.executeQuery();
                while (rs.next()) {
                    System.out.print("Column 1 returned ");
                    System.out.println(rs.getString(1));
                }
                rs.close();
                pst.close();

                con.setAutoCommit(false);
                Statement st = con.createStatement();

                st.setFetchSize(3);
                rs = st.executeQuery("SELECT * FROM mytable");
                while (rs.next()) {
                    System.out.print("a row was returned.");
                    System.out.println(rs.getString(1));
                }
                rs.close();

                st.setFetchSize(0);
                rs = st.executeQuery("SELECT * FROM mytable");
                while (rs.next()) {
                    System.out.print("many rows were returned.");
                    System.out.println(rs.getString(1));
                }
                rs.close();

                st.close();
                st = con.createStatement();
                st.executeUpdate("INSERT INTO test VALUES(1)");


            } catch (Exception e) {
                System.err.println(e);
                System.exit(0);

            }
        }