code:

Connection con = null;
        PreparedStatement pst = null;

        String url = "jdbc:postgresql://localhost/testdb";
        String user = "user12";
        String password = "34klq*";

        try {

            int id = 6;
            String author = "Trygve Gulbranssen";
            con = DriverManager.getConnection(url, user, password);

            String stm = "INSERT INTO authors(id, name) VALUES(?, ?)";
            pst = con.prepareStatement(stm);
            pst.setInt(1, id);
            pst.setString(2, author);                    
            pst.executeUpdate();

        } catch (SQLException ex) {
            Logger lgr = Logger.getLogger(Prepared.class.getName());
            lgr.log(Level.SEVERE, ex.getMessage(), ex);

        } finally {

            try {
                if (pst != null) {
                    pst.close();
                }
                if (con != null) {
                    con.close();
                }

            } catch (SQLException ex) {
                Logger lgr = Logger.getLogger(Prepared.class.getName());
                lgr.log(Level.SEVERE, ex.getMessage(), ex);
            }
        }