How To Make A Scrolling Background In Java

i am trying to make a platform game in java and to do this im trying to make a scrolling bacground. i can get the background image to scroll. However, i cant get the image to scroll forever, here is the code.

GamePanel class ( the jpanel )
public class GamePanel extends JPanel implements ActionListener{
static ArrayList<BackGround> store = new ArrayList<BackGround>();
public GamePanel(){
setFocusable(true);
Timer time = new Timer(5,this);
time.start();
store.add(new BackGround(0,-200));

the problem i have is that i want the bacground to loop. however, once the first instance of the background is done scrolling it freezes and doesnt load anymore. here is the code for adding a new background to the list

if(store.get(a).getX() <= -950 ){
GamePanel.store.get(a).setX(-900);
GamePanel.store.add(new BackGround(-951,-200));
}