Mysterious ClassNotFoundException when Android system uses BackupAgent

Question

I have several (4) error reports in my application when the Android system decides to back up in the Google Cloud using BackupAgent. I am using SharedPreferencesBackupHelper. The stack trace looks like this (my real package name is replaced below with com.xxx.yyy):

java.lang.RuntimeException: Unable to create BackupAgent com.xxx.yyy.MyBackupAgent: java.lang.ClassNotFoundException: com.xxx.yyy.MyBackupAgent in loader dalvik.system.PathClassLoader[/mnt/asec/com.xxx.yyy-1/pkg.apk] at android.app.ActivityThread.handleCreateBackupAgent(ActivityThread.java:2114) at android.app.ActivityThread.access$3200(ActivityThread.java:132) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1138) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:143) at android.app.ActivityThread.main(ActivityThread.java:4196) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:507) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.ClassNotFoundException: com.xxx.yyy.MyBackupAgent in loader dalvik.system.PathClassLoader[/mnt/asec/com.xxx.yyy-1/pkg.apk] at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240) at java.lang.ClassLoader.loadClass(ClassLoader.java:551) at java.lang.ClassLoader.loadClass(ClassLoader.java:511) at android.app.ActivityThread.handleCreateBackupAgent(ActivityThread.java:2064) ... 10 more 

I even had an accident with the program when I myself, on my own phone running Android 2.3.3. What puzzles me with this program is that I know for sure that the "MyBackupAgent" class is present in the package. I also know for sure that backing up to the cloud works on the same phone where I once crashed.

I searched quite a bit on the net to solve a problem that might be causing this problem. All cases that I found with similar problems, that is, a ClassNotFoundException exception, is thrown from PathClassLoader, although the class is present in apk, has one thing in common. They all have trailing "-1" or "-2" and the end of the package name directory where apk is installed.

In my error reports, these are different names, where dalvik.system.PathClassLoader searches for my reservation class:

/mnt/asec/com.xxx.yyy-1/pkg.apk

/data/app/com.xxx.yyy-1.apk

/mnt/asec/com.xxx.yyy-2/pkg.apk

I may be fishing in the wrong lake here, but what do these “-1” and “-2” mean at the end of the package name directory, and can there be a problem with this? I doubt that the problem lies in my code, since just tell the system to schedule a backup of my sharedpreferences. The Android system then triggers the backup action at an appropriate time in the future - and this happens in the event of a failure. Considering the stack trace, my code is not even mentioned. All system procedures end with a search for my backup class in apk and, for some unknown reason, may not find it.

I did not set the android: name attribute in the application tag in the manifest, which, as I read, could cause a similar error.

Does anyone know what can do this? Or better yet, how to avoid it.

Answer 1

Prefix

"/ mnt / asec" means that the phone is connected to the computer, and during the time the application tries to start or tries to back up (the application is no longer in use), it fails. It is expected that the phone will be installed.

Answer 2

I am experiencing the same collapse. One of the theories I'm curious about is whether to specify a relative or absolute package name.

In my case, I used "android: name =" because my application extends the application. So I used: android.name = "com.foo.bar.myapp" instead: android.name = "MyApp"

It doesn't seem to be changing, but I wonder if the bootloader uses a different package name, for example, with the suffix "-1" or "-2".