Thread: display item for item selected in combobox

Hi i have table sql with 2 columns i diplay in jCombobox a data from the first column and when i selectItem i want display a message that contains item corresponded if the second columns
this is the code he always gives me 0

conn = DriverManager.getConnection("jdbc:mysql://localhost/etat", "root", "123456"); 
            String sql = "SELECT * FROM pop;";         
            PreparedStatement prest = conn.prepareStatement(sql);
            ResultSet res=prest.executeQuery();
    while(res.next()){ 
             jComboBox3.addItem(res.getString("name")) ; 
             jComboBox3.setActionCommand(res.getString("etat_syn"));           
    }
 if(jComboBox3.getSelectedItem()!=null){
        System.out.println("Command: " + jComboBox3.getActionCommand());