Android: Unable to instantiate application

In my case it throws:

Caused by: java.lang.IllegalAccessException: java.lang.Class<foo.bar.MyApp> is not accessible from java.lang.Class<android.app.AppComponentFactory>

The reason is the Application class must be declared with the modifier public, e.g. do this:

public class MyApp extends Application {
}

instead of:

class MyApp extends Application {
}

For me, the issue was with instant-run. Disabling it solved the issue.

Will update if I find a solution for re-enabling and making it work.

Let's assume, that your projects base package is really Application, as you've stated it in the manifest.

If your MyApplication class is inside this package (the package declaration of the class is package Application;), then the application element in your androidManifest.xml should look like

<application android:name=".MyApplication" [...]

If this MyApplication class is inside the Application.app package (package Application.app;), then in the manifest you should write:

<application android:name=".app.MyApplication" [...]

If you didn't extend the android.app.Application (you don't have a MyApplication extends android.app.Application class), just wanted to set a name to your application, remove it this attribute, since it says to the compiler that there is an Application extension that should be instantiated instead of the default android.app.Application.

And finally, if the first assumption is wrong, and you've changed for any reason the package declaration in your androidManifest's manifest element, undo it or update your classes to be in that package.