Hello,
I have two JComboBoxs, the first one is filled from database, the second one is filled after user's choice on the first comboBox.
Once a choice in second comboBox is done, some JLabels are filled from database.

The problem is that when I select an item in the first combobox and then I change the choice thr first item is always present and the second is added with dupplicates.

final JComboBox comboBox1 = new JComboBox();  
 
final JComboBox comboBox2 = new JComboBox();  
 
 
        try {         
 
            String sql = "Select matricule FROM clients";  
            rs = stat.executeQuery(sql);  
            comboBox1.addItem("Select item");  
            while(rs.next()) {  
                comboBox1.addItem(rs.getInt("matricule"));  
            }  
 
 
        } catch (SQLException e) {            
            e.printStackTrace();  
        }  
 
        comboBox1.addItemListener(new ItemListener() {  
            public void itemStateChanged(ItemEvent arg0) {                 
 
                int matricule =  (Integer) comboBox1.getSelectedItem();  
                String sqll = "Select  * FROM clients WHERE matricule = " +matricule;  
 
                try {  
                    rs = stat.executeQuery(sqll);                     
 
                    while(rs.next()) {  
                        nom.setText(rs.getString("nom"));  
                        prenom.setText(rs.getString("prenom"));  
                        cin.setText(rs.getString("cin"));  
                        adresse.setText(rs.getString("adresse"));                     
                    }  
 
                } catch (SQLException e) {  
                    // TODO Auto-generated catch block  
                    e.printStackTrace();  
                }  
 
 
                String sql = "Select  DISTINCT p.code FROM parcelle p, clients c WHERE c.matricule = p.exploitant AND c.matricule = " +matricule;  
 
                try {  
                    rs = stat.executeQuery(sql);                          
 
                    while(rs.next()) {  
 
                        comboBox2.addItem(rs.getInt("code"));  
                    }  
 
                } catch (SQLException e) {  
                    // TODO Auto-generated catch block  
                    e.printStackTrace();  
                }  
 
 
 
            }  
        });       
 
 
        comboBox1.setBounds(154, 317, 105, 20);  
        contentPane.add(comboBox1);       
 
 
        comboBox2.addItemListener(new ItemListener() {  
            public void itemStateChanged(ItemEvent arg0) {             
 
                int code =  (Integer) comboBox2.getSelectedItem();  
                String sqll = "Select  * FROM parcelle WHERE code = " +code;  
 
                try {  
                    rs = stat.executeQuery(sqll);                     
 
                    while(rs.next()) {  
                        sau.setText(rs.getString("sau"));  
                        sol.setText(rs.getString("type_sol"));  
                        irrigation.setText(rs.getString("mode_irrigation"));  
                        exploitation.setText(rs.getString("type_exploitation"));                      
                    }  
 
                } catch (SQLException e) {  
                    // TODO Auto-generated catch block  
                    e.printStackTrace();  
                }  
            }  
        });  
        comboBox2.setBounds(154, 423, 105, 20);  
        contentPane.add(comboBox2);