Android: Rare and Non-Reproducible ClassNotFoundException

Question

I have a published app that gets reports about a ClassNotFoundExceptionfrom users that I went beyond my wits end trying to fix. I have not been able to reproduce this crash and similar instances of this error here on SO have either been cases of incorrect path to a dependency or a different package in the MainActivity than the manifest.

The issues with the wrong path to the dependencies are an Eclipse thing, while all the other errors could be easily fixed with Android Studio's "sync" and "clean project" (which I did to no avail).

I've triple checked all the package names and did not find any discrepancies.

Here is my manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.johan.fsc">

    <uses-permission android:name = "android.permission.VIBRATE"/>
    <uses-permission android:name="com.android.vending.BILLING" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/logo"
        android:label="@string/app_name"
        android:fullBackupContent="true">
        <activity
            android:name="com.johan.fsc.MainActivity"
            android:screenOrientation="portrait"
            android:label="@string/app_name"
            android:theme="@style/splashscreenTheme"
            android:hardwareAccelerated="false"
            android:largeHeap="true">>
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <activity android:name = "com.johan.fsc.SettingsActivity"
            android:theme="@style/PreferencesTheme"/>
    </application>

Here is the error report I always get from users:

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.johan.fsc/com.johan.fsc.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.johan.fsc.MainActivity" on path: DexPathList[[zip file "/data/app/com.johan.fsc-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2595)
    at android.app.ActivityThread.access$800(ActivityThread.java:178)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1470)
    at android.os.Handler.dispatchMessage(Handler.java:111)
    at android.os.Looper.loop(Looper.java:194)
    at android.app.ActivityThread.main(ActivityThread.java:5624)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.johan.fsc.MainActivity" on path: DexPathList[[zip file "/data/app/com.johan.fsc-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
    at android.app.Instrumentation.newActivity(Instrumentation.java:1071)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
    ... 10 more
    Suppressed: java.io.IOException: Failed to open oat file from dex location '/data/app/com.johan.fsc-1/base.apk'
        at dalvik.system.DexFile.openDexFileNative(Native Method)
        at dalvik.system.DexFile.openDexFile(DexFile.java:295)
        at dalvik.system.DexFile.<init>(DexFile.java:80)
        at dalvik.system.DexFile.<init>(DexFile.java:59)
        at dalvik.system.DexPathList.loadDexFile(DexPathList.java:262)
        at dalvik.system.DexPathList.makeDexElements(DexPathList.java:231)
        at dalvik.system.DexPathList.<init>(DexPathList.java:109)
        at dalvik.system.BaseDexClassLoader.<init>(BaseDexClassLoader.java:48)
        at dalvik.system.PathClassLoader.<init>(PathClassLoader.java:65)
        at android.app.ApplicationLoaders.getClassLoader(ApplicationLoaders.java:57)
        at android.app.LoadedApk.getClassLoader(LoadedApk.java:370)
        at android.app.LoadedApk.makeApplication(LoadedApk.java:562)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4818)
        at android.app.ActivityThread.access$1500(ActivityThread.java:178)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1531)
        ... 7 more
Caused by: java.io.IOException: Failed to open oat file from /data/app/com.johan.fsc-1/arm/base.odex (error Failed to open oat filename for reading: No such file or directory) (no dalvik_cache availible) and relocation failed.
        ... 22 more
Caused by: java.io.IOException: 
        ... 22 more
Caused by: java.io.IOException: Failed to remove obsolete file from /data/dalvik-cache/arm/data@[email protected]@[email protected] when searching for dex file /data/app/com.johan.fsc-1/base.apk: Permission denied
        ... 22 more
    Suppressed: java.lang.ClassNotFoundException: com.johan.fsc.MainActivity
        at java.lang.Class.classForName(Native Method)
        at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
        at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
        ... 13 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available/output.

It would seem that the culprit is java.io.IOException: Failed to remove obsolete file from /data/dalvik-cache/arm/data@[email protected]@[email protected] when searching for dex file /data/app/com.johan.fsc-1/base.apk: Permission denied, but I have not found why it's being invoked for some users and not the majority, and more importantly--how to fix it.

Answer 1

Possible Cause 1: There is a typo in the manifest in the line android:largeHeap="true">>. xml line ends with >>. This may be preventing the Intent-Filter from executing.

Possible Cause 2: My guess is that the phone is searching for a class <PackageName>.<PackageName>.<ClassName> instead of <PackageName>.<ClassName> . So definitely <PackageName>.<PackageName>.<ClassName> is not found and ClassNotFoundException would be the result. In android studio, in the manifest, by default activity name is written like this: android:name=".<ClassName>" instead of android:name="<PackageName>.<ClassName>" . You can give this a try.

Most phones may be checking whether packagename is added before the class name in the manifest. If it is added then they don't add it while searching of the class. While few phones must be adding the package name by default while searching for the class. Hence, they cannot find your class.