執行有錯誤

URL url = MyImageIcon.class.getResource("cloud.png"); Icon icon = new ImageIcon(url);
我將程式執行, 有以上代碼. 出現以下錯誤:

run: Exception in thread "main" java.lang.NullPointerException

at javax.swing.ImageIcon.(ImageIcon.java:205)

at swing.MyImageIcon.(MyImageIcon.java:15) at swing.MyImageIcon.main(MyImageIcon.java:28) Java Result: 1 BUILD SUCCESSFUL (total time: 1 second)

public ImageIcon (URL location) { this(location, location.toExternalForm());

把cloud.png放在以下目錄, 即解決. (...)Documents\NetBeansProjects\MyImageIcon\build\classes\swing