android classcastexception on activity startup

i have a simple activity program in android. basically the class just extends Activity. But when i start it i get a ClassCastException in the constructor of my class. i dont even have a constructor defined, so it must be in the constructor of the superclass which is Activity.

unfortunately the debugger doesnt give any detailed information on what class it is trying to cast.

here is the stacktrace:

Thread [<1> main] (Suspended (exception RuntimeException))  
    ActivityThread$PackageInfo.makeApplication(boolean, Instrumentation) line: 649  
    ActivityThread.handleBindApplication(ActivityThread$AppBindData) line: 4232 
    ActivityThread.access$3000(ActivityThread, ActivityThread$AppBindData) line: 125    
    ActivityThread$H.handleMessage(Message) line: 2071  
    ActivityThread$H(Handler).dispatchMessage(Message) line: 99 
    Looper.loop() line: 123 
    ActivityThread.main(String[]) line: 4627    
    Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]  
    Method.invoke(Object, Object...) line: 521  
    ZygoteInit$MethodAndArgsCaller.run() line: 868  
    ZygoteInit.main(String[]) line: 626 
    NativeStart.main(String[]) line: not available [native method]  

and when I look into the runtimeexception I get:

detailMessage "Unable to instantiate application com.test.MyApp: java.lang.ClassCastException: com.test.MyApp" (id=830067694464)

the only code is

package com.test;
import android.app.Activity;
public class MyApp extends Activity {

}