java swing Jpanel 窗口 面板刷新 面板滾動條

ArrayList<Sign> sing = new DataHandle().getSignByCourse(ArrayData.courseID);
				pnSign.removeAll();
				// removeall();
				userInit(sing);
				pnSign.repaint();

this.pnSign.setPreferredSize(new Dimension(600,5000));
		sp = new JScrollPane(pnSign);// 滾動條
		sp.setBounds(0, 10, 200, 70);