Android Activity: ClassNotFoundException

Question

my android app was running fine until I added some classes and edited the manifest file.

Now, when I try to run or debug the app on my android emulator with android 2.2, the app crashes and I get a ClassNotFoundException as follows:

D/AndroidRuntime(  275): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
D/AndroidRuntime(  275): CheckJNI is ON
D/AndroidRuntime(  275): --- registering native functions ---
I/ActivityManager(   59): Starting activity: Intent { act=android.intent.action.MAIN     cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=de.bastian.gpstracker/.MainActivity }
I/ActivityManager(   59): Start proc de.bastian.gpstracker for activity de.bastian.gpstracker/.MainActivity: pid=281 uid=10036 gids={}
D/AndroidRuntime(  275): Shutting down VM
D/jdwp    (  275): adbd disconnected
D/AndroidRuntime(  281): Shutting down VM
W/dalvikvm(  281): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
E/AndroidRuntime(  281): FATAL EXCEPTION: main
E/AndroidRuntime(  281): java.lang.RuntimeException: Unable to instantiate application de.bastian.gpstracker: java.lang.ClassNotFoundException: de.bastian.gpstracker in loader dalvik.system.PathClassLoader[/data/app/de.bastian.gpstracker-1.apk]
E/AndroidRuntime(  281):        at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:649)
E/AndroidRuntime(  281):        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4232)
E/AndroidRuntime(  281):        at android.app.ActivityThread.access$3000(ActivityThread.java:125)
E/AndroidRuntime(  281):        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2071)
E/AndroidRuntime(  281):        at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(  281):        at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(  281):        at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(  281):        at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(  281):        at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(  281):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(  281):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(  281):        at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(  281): Caused by: java.lang.ClassNotFoundException: de.bastian.gpstracker in loader dalvik.system.PathClassLoader[/data/app/de.bastian.gpstracker-1.apk]
E/AndroidRuntime(  281):        at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
E/AndroidRuntime(  281):        at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
E/AndroidRuntime(  281):        at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
E/AndroidRuntime(  281):        at android.app.Instrumentation.newApplication(Instrumentation.java:942)
E/AndroidRuntime(  281):        at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:644)
E/AndroidRuntime(  281):        ... 11 more
W/ActivityManager(   59):   Force finishing activity de.bastian.gpstracker/.MainActivity
D/dalvikvm(  149): GC_FOR_MALLOC freed 4092 objects / 248904 bytes in 134ms
W/ActivityManager(   59): Activity pause timeout for HistoryRecord{43fa91d0 de.bastian.gpstracker/.MainActivity}
I/ActivityManager(   59): Displayed activity com.android.launcher/com.android.launcher2.Launcher: 12561 ms (total 12561 ms)
W/ActivityManager(   59): Activity destroy timeout for HistoryRecord{43fa91d0 de.bastian.gpstracker/.MainActivity}
D/KeyguardViewMediator(   59): pokeWakelock(5000)
D/KeyguardViewMediator(   59): pokeWakelock(5000)
I/ARMAssembler(   59): generated scanline__00000177:03515104_00001001_00000000 [ 91 ipp] (114 ins) at [0x325a10:0x325bd8] in 590637 ns
I/ARMAssembler(   59): generated scanline__00000077:03515104_00000000_00000000 [ 33 ipp] (47 ins) at [0x3261f0:0x3262ac] in 261841 ns
W/WindowManager(   59): No window to dispatch pointer action 1
I/Process (  281): Sending signal. PID: 281 SIG: 9
I/ActivityManager(   59): Process de.bastian.gpstracker (pid 281) has died.

I guess it's something wrong with my project configuration. Here is my manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="de.bastian.gpstracker"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="10" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme"
        android:name="de.bastian.gpstracker" >
        <activity
            android:name="de.bastian.gpstracker.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

To be honest, I do not remember the last changes I made to this file, but, to me, everything seems to be fine here.

While searching for a sultion, I also came along the link Android Activity ClassNotFoundException - tried everything, which describes the same problem, but has a solution no applicable to my case as I am only working with a single project.

In the error log above, I noticed that the file name of the apk created ends on a '-1'. Maybe that's an error, maybe that's simply how eclipse/adt handles things. Also, I noticed that, when I try to run/debug the project, multiple class files with names MainActivity.class, MainActivity$1.class, MainActivity$2.class are created, although I only have a single MainActivity.java file (and no MainActivity$2.file or anything like that).

It would be great if someone had an idea of what's going wrong here.

Answer 1

Change your application tag in manifest to this:

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="de.bastian.gpstracker.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

Remove the name attribute from the application tag. It, misleadingly, does not have anything to do with the name of your app and is actually the name of an extra class to load before loading your application. That's why you are getting the ClassNotFoundException. Remove it and it should work:

Answer 2

You are setting the application node to reference a nonexistent class

de.bastian.gpstracker

Refers to the package name, no class whatsoever. Since gpstracker is the last thing in that string, the class loader assumes that gpstracker is a class, tries to load it and fails.

So write the name of the Application class (which extends Application).

Eg

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme"
        android:name="de.bastian.gpstracker.MyApplicationClass" >

If you don't have a class that extends Application, then take out the android:name attribute for this node so it looks just like:

<application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >