ui/src/main/java/ucar/nc2/ui/geoloc/Rubberband.java
public void end(Point p) {
    lastPt.x = endPt.x = p.x;
    lastPt.y = endPt.y = p.y;

    Graphics2D g = (Graphics2D) component.getGraphics();
    if(g != null) {
     try {
       g.setXORMode(component.getBackground());
       drawLast(g);
     }
     finally {
       g.dispose();
     }
    }
  }
public void end(Point p) {
    lastPt.x = endPt.x = p.x;
    lastPt.y = endPt.y = p.y;

    Graphics2D g = (Graphics2D) component.getGraphics();
    if(g != null) {
     try {
       g.setXORMode(component.getBackground());
       drawLast(g);
     }
     finally {
       g.dispose();
     }
    }
  }
Last point, done with drawing.