Redrawing Lines

Ok so I’m trying to store vertexes in a linked list so when the screen is cleared the lines disappear but when i click on redraw in the menu the lines come back up. this is what i have in my code, it seems that i cant get them to come back up

This first part is where i actually store the points into the linked list. i tested the code to see if the points were storing and it does


......(more code above that doesn't matter)
public void mousePressed(MouseEvent e)
{
     if (gui.getCurrentMode() == "Draw Line")
     {
          if (num_points == 0)
          {
               x0 = e.getX();
               y0 = e.getY();
               list.add(x0);
               list.add(y0);
               num_points++;
          }
          else if (num_points == 1)
          {
               x1 = e.getX();
               y1 = e.getY();
               list.add(x1);
               list.add(y1);
               canvas.display();
               num_points++; 
          }
     }
......(more code that works the same)

So now to actually draw out the lines here is the code i have.


........
else if (gui.getCurrentMode() == "Redraw Image")
    {
          gl.glBegin(gl.GL_LINES);
          (color code)
          gl.glVertex2i(list.get(0), list.get(1));
          gl.glVertex2i(list.get(2), list.get(3));
          gl.glEnd();
     }

i was wondering why nothing shows up when i click on the Redraw image selection when its picked in the menu