private void jButton15ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton15ActionPerformed
        // TODO add your handling code here:
        liceu.Administrator admin = new liceu.Administrator(usernameElev.getText(), parolaElev.getText(),ncElev.getText(),cnpElev.getText(),"Elev",(String)clasaElev.getSelectedItem());
        admin.addUser();
        usernameElev.setText("");
        parolaElev.setText("");
        ncElev.setText("");
        cnpElev.setText("");
        
        int i;
        BufferedReader fisier;
        try {
            fisier = new BufferedReader(new FileReader("credentials"));
            listModelElevi.clear();
            ArrayList<String> vector = new ArrayList<>();
            for(String line; (line = fisier.readLine())!= null;){
                vector.add(line);                  
            }            
            for(i=0;i<vector.size();i=i+5){
                if(vector.get(i+4).equals("Elev"))
                   listModelElevi.addElement(vector.get(i));
            }
        } catch (FileNotFoundException ex) {
            Logger.getLogger(Administratorapp.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(Administratorapp.class.getName()).log(Level.SEVERE, null, ex);
        }
    }//GEN-LAST:event_jButton15ActionPerformed