java - how to populate jcombobox with arrays that match specific criteria -

when try code below list isn't populated specific arrays please i'm pretty new coding gui in netbeans

private void bookinglistjcbactionperformed(java.awt.event.actionevent evt) {                                                     for(int = 0;i<datasource.getbookinglist().size();i++){         bookings tempbooking = datasource.getbookinglist().get(i);          boolean tempfinish = tempbooking.getfinish();         string tempmechanic = tempbooking.getmechanic();         string tempclerk = tempbooking.getclerk();         string tempservice  = tempbooking.getservice();         if(tempfinish == true){          bookinglistjcb.additem(tempbooking);          mechanicjtf.settext(tempmechanic);          serivececlerkjtf.settext(tempmechanic);          servicejtf.settext(""+tempservice );          finishjtf.settext(""+tempfinish);         }     }       // todo add handling code here: }  

here bookings class how don't know why combo box isn't displaying anything

public class bookings { private string vehicle; private string clerk; private string service; private string mechanic; private boolean finish;  public bookings() { }  public bookings(string vehicle, string clerk, string service, string mechanic, boolean finish) {     this.vehicle = vehicle;     this.clerk = clerk;     this.service = service;     this.mechanic = mechanic;     this.finish = finish; }  public string getvehicle() {     return vehicle; }  public void setvehicle(string vehicle) {     this.vehicle = vehicle; }  public string getclerk() {     return clerk; }  public void setclerk(string clerk) {     this.clerk = clerk; }  public string getservice() {     return service; }  public void setservice(string service) {     this.service = service; }  public string getmechanic() {     return mechanic; }  public void setmechanic(string mechanic) {     this.mechanic = mechanic; }  public boolean getfinish() {     return finish; }  public void setfinish(boolean finish) {     this.finish = finish; }  @override public string tostring() {     return "bookings{" + "vehicle=" + vehicle + ", clerk=" + clerk + ", service=" + service + ", mechanic=" + mechanic + ", finish=" + finish + '}'; }  

}