在JPanel中绘制捕获的屏幕图像，再显示一次图像?如何修改为只显示一次?

I Want to capture Image from screen and draw it in JPanel , it works but it is displayed one more time like entering in a loop , I am confused by this , How can I fix it ,Please? Varibles Iwidth,Ihieght ares above initiaized, but I take the block of code that cause the problem I Want to capture Image from screen and draw it