Android :: Simple Program - Class Extends Activity At 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 don't even have a constructor defined, so it must be in the constructor of the superclass which is Activity. Unfortunately the debugger doesn't 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 this 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 {
}