public String getEmail(){
        try {
            Connection con = DriverManager.getConnection("jdbc:mysql://localhost/metairline", "root", "");
            PreparedStatement st;
            String sql = "SELECT Email FROM Korisnik WHERE Username = ?";
            st = con.prepareStatement(sql);
            st.setString(1, Prijava.username);
            st.execute();
            ResultSet rs = st.getResultSet();

            if(rs.next()) {
                return rs.getString("Email");
            }
        } catch (SQLException ex) {
            Logger.getLogger(Prijava.class
                    .getName()).log(Level.SEVERE, null, ex);
        }
        return null;

    }