Invoke the appletviewer and try the save option. You should get:
Unknown object of type:java.io.FileNotFoundException
Exception occurred during event handling:
java.lang.IllegalArgumentException: Unknown argument
at java.text.MessageFormat.format(MessageFormat.java)
at java.text.MessageFormat.format(MessageFormat.java)
at java.text.Format.format(Format.java)
at sun.applet.AppletMessageHandler.getMessage(AppletMessageHandler.java:63)
at sun.applet.AppletViewer.appletSave(AppletViewer.java:422)
at sun.applet.AppletViewer.handleEvent(AppletViewer.java:631)
at java.awt.Window.postEvent(Window.java)
at java.awt.MenuComponent.postEvent(MenuComponent.java)
at java.awt.MenuComponent.postEvent(MenuComponent.java)
at java.awt.MenuComponent.postEvent(MenuComponent.java)
at java.awt.MenuComponent.dispatchEventImpl(MenuComponent.java)
at java.awt.EventDispatchThread.run(EventDispatchThread.java)