String val = txt_val.getText();
    String col = txt_col.getText();
     Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try{
    Class.forName("com.mysql.jdbc.Driver");
    conn = DriverManager.getConnection("jdbc:mysql://localhost/net","root","");

pstmt.setString(1,val);
    pstmt.setString(2,val);

   pstmt.setString(3,col);
   pstmt.setString(4,col);


    int i = pstmt.executeUpdate();
    if(i>0)
    {
        JOptionPane.showMessageDialog(null,"done");
    }
    else
    {
        JOptionPane.showMessageDialog(null,"query failed");
    }


    }

    catch(Exception e){
     JOptionPane.showMessageDialog(null,e);
    }


}