unable to instantiate application - ClassNotFoundException
android
Solution
There are two possibilities. Either you, like me, have a spelling error in your manifest file. Have a co-worker or friend read it to make sure the name is correct. Or you have not referenced the project correctly.
The official document describes how to properly link projects in its documentation.
Why it would first seem to work and later stop working is a bit of a mystery. However, I guess that the VM might still have had the necessary references ready to resolve the classes in the library just fine. A restart of the VM removed all those references and trying to resolve them was unsuccessful.
Update: Regarding the edits in the OP: As you confirm that you have correctly referenced the other project, you can check if the project is included in APK, just to be sure. You can rename and open an APK as any other archive (.rar works fine for me). Sometimes, it happened to me, the project is not correctly included in the APK. A cleaning of your workspace usually remedies the problem and so could a restart of your IDE depending on what you are using. To manually conduct a clean in Eclipse for example, use `Project->Clean...` or try `Android Tools->Fix Project Properties` by right-clicking on your project.
As you seem to also have fixed the problem by restarting your device, it could be that the libraries were linked incorrectly. A problem that I have never seen myself but as a very common quote says: "Have you tried turning it off and on again?".
Problem
EDIT: This problem has not already been resolved in the other suggested SO question I had a fully working app on the market for over a year, with very few crash reports. Then recently I changed my app into a library, so that it could be included within multiple different "wrapper" projects. This was so that I could easily make different version - free, paid, non-google markets, with/without in-app purchasing etc etc. The new "library+wrapper" app appeared to work fine. I could run it multiple times, without error. But then a day later (when presumably the OS had closed some or all of the app's activities) I tried to run it and it reported ``` Unable to instantiate application com.mycompany.mygamelibrary.MyGameApplicationClass: java.lang.ClassNotFoundException: com.mycompany.mygamelibrary.MyGameApplicationClass ``` The class it failed to find is the first class that runs when the program starts up, MyGameApplicationClass - which extends `Application`. This class is part of the library. I suspect something goofy in one of the two manifest files. The manifest of the wrapper project contains the lines... ``` <application android:icon="@drawable/mygame_icon" android:screenOrientation="portrait" android:label="My Game Name" android:name="com.mycompany.mygamelibrary.MyGameApplicationClass"> ``` Any ideas what could have gone wrong? EDIT: The library was referenced "the correct way" as defined by yorkw's answer to this SO question. EDIT: I can not repeat the crash at the moment :-( I don't know what it is the OS does when the app is not used for a day or two.