Problem with Startup() SingleFrameApplication Warning: getApplicationResourceMap(): no Application class

I created a project with NetBeans. I did a class that checkForUpdates. If there are it does the updgrade otherwise it starts main project class.

The problem is when i Create object of MyClassApp and i launch with myClass.startup() i got those errors....I thought that was my update class so I tryed with a normal main without anything just create MyClassApp and launch startup() but it gets the same errors.

How can i fix it?

26-set-2011 12.34.32 org.jdesktop.application.ResourceManager getApplicationResourceMap
WARNING: getApplicationResourceMap(): no Application class
26-set-2011 12.34.36 org.jdesktop.application.SingleFrameApplication initRootPaneContainer
WARNING: couldn't restore sesssion [mainFrame.session.xml]
java.lang.NullPointerException
    at org.jdesktop.application.LocalStorage.getApplicationId(LocalStorage.java:195)
    at org.jdesktop.application.LocalStorage.getDirectory(LocalStorage.java:234)
    at org.jdesktop.application.LocalStorage$LocalFileIO.openInputFile(LocalStorage.java:330)
    at org.jdesktop.application.LocalStorage.openInputFile(LocalStorage.java:76)
    at org.jdesktop.application.LocalStorage.load(LocalStorage.java:138)
    at org.jdesktop.application.SessionStorage.restore(SessionStorage.java:382)
    at org.jdesktop.application.SingleFrameApplication.initRootPaneContainer(SingleFrameApplication.java:231)
    at org.jdesktop.ap开发者_JS百科plication.SingleFrameApplication.show(SingleFrameApplication.java:463)

I don't know what causes this error, but I have a solution.

You probably have a class as defined below:

public class MyClassApp extends SingleFrameApplication {
  ...
  @Override protected void startup() {
    show(new MyClassApp (this));
  }
  ...
  public static MyClassApp getApplication() {
    return Application.getInstance(MyClassApp.class);
  }
  ...
}

If you start your application with

MyClassApp.getApplication().startup();

You probably won't get any error.