java.lang.ClassNotFoundException on working app

I have created and published my first Android app. It's very simple. It works fine on simulator and some phones, but I am getting this error:

java.lang.RuntimeException: Unable to instantiate application cz.teamnovak.droid.Novak ESC Track guide: java.lang.ClassNotFoundException: cz.teamnovak.droid.Novak ESC Track guide in loader dalvik.system.PathClassLoader[/data/app/cz.teamnovak.droid-1.apk]
    at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:649)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4232)
    at android.app.ActivityThread.access$3000(ActivityThread.java:125)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2071)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4627)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: cz.teamnovak.droid.Novak ESC Track guide in loader dalvik.system.PathClassLoader[/data/app/cz.teamnovak.droid-1.apk]
    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
    at android.app.Instrumentation.newApplication(Instrumentation.java:942)
    at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:644)
    ... 11 more

Any idea what can cause this?

Yep, I had this exact same problem. It was because I specified the android:name attribute in the application node in the manifest file.

Your Android Manifest file probably looks something like this:

   <application 
       android:name="Novak ESC Track guide" 
       android:icon="@drawable/icon" 
       android:label="@string/app_name" 
       android:description="@string/help_text" >

Do not use the android:name attribute! unless you've implemented a custom Application object.

The application:name attribute has nothing to do with the name of your app. This is the name of a specific class to load as your Application instance. That's why you would get the ClassNotFoundException if that class wouldn't exist.

For the name of the app use the android:label attribute on this same application node instead.

Remove it and it should work:

<application 
    android:icon="@drawable/icon" 
    android:label="@string/app_name" 
    android:description="@string/help_text" >

Something like this happened when I changed the build target to 3.2. After digging around I found that a had named the jar lib folder "lib" instead of "libs". I just renamed it to libs and updated the references on the Java build path and everything was working again. Maybe this will help someone...

We have a couple of projects where this issue was logged from time to time on the Android Market. I found the following issues in the manifests:

1. If the package name is com.test then activities names should be .ActivityName (with a leading dot), not just ActivityName.

2. For some classes, those that appeared in the logs most often, the class name was specified as com.test.Name while it should have been .Name.

I guess many implementations of Android handle these minor issues successfully (this is why the exception never happened in testing), while others few are throwing the exception.

Had the same error: java.lang.RuntimeException: Unable to instantiate activity (classnotfound) FIRST try to change the build platform (2.3.3 -> 2.2 -> 2.3.3) worked for me.

This is my observation with respect to the Error. I recently Updated the ADT to 22.0.1. I am getting following Error when i imported my previous Projects "E/AndroidRuntime(24807): Caused by: java.lang.ClassNotFoundException: com.sherl.sherlockfragmentsapp.StartActivity in loader dalvik.system.PathClassLoader[/data/app/com.sherl.sherlockfragmentsapp-1.apk]"

Then I changed "Properties->Java Build Path-> Order and Export" in the following manner [Unable to add the Image because of the Forum rules]

1. Android Private Libraries - checked
2. Android 4.2.2 - unchecked
3. Android Dependencies - checked
4. /src - selected
5. /gen - selected

It resolved the issue. Hope this is Help you guys.

I know this question has been answered, and it likely wasn't the case. But I was getting this error, and figured I'd post why in case it can be helpful to anyone else.

So I was getting this error, and after several hours sheepishly realized that I had unchecked 'Project > Build Automatically'. So although I had no compilation errors, this is why I was getting this error. Everything started working as soon as I realized that I wasn't actually building the project before deploying :-/

Well, that's my story :-)

Had this sort of problem today after upgrading to latest ADT/SDK. Took me quite a while. Checked that i used google-apis (for maps), uses-library, cleaned the project etc.

Deleting the .project and adding a fresh one (create new android project) finally solved it.

I have this problem sometimes with eclipse. What has corrected it for me is to go to Project Properties / Android and change the build target API to a different version and republish. I'll find that corrected it, then I can change it back to the desired build target.

or

You may need to check your proguard.cfg.

Assuming you have linked your libraries properly and that your library projects have the code you need marked for export, the next step you might want to do is to check your proguard settings and make sure you are not stripping out the classes you need.

I was struggling with this quite a bit after I had my app working going directly to the emulator or device from eclipse. The problem I was having was after the app was published (i.e. gone through proguard) and run on the device it was missing classes that were contained in the project. They were being stripped out somehow.

My problem may have been caused when I had tried to use IntelliJ and have switched back to eclipse.

Here is the proguard file that worked for me:

-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*

-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService

-keepclasseswithmembers class * {
    native <methods>;
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}

-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}

I got this error when I ran my app on earlier versions of android. I thought http://developer.android.com/reference/android/widget/SearchView.html">SearchView</a> was backwards compatible to Android 1.5, but it was created in 3.0. I removed its reference from the code and it worked.

In my case I had to add android:name=".activity.SkeletonAppActivity" instead of android:name=".SkeletonAppActivity" in the manifest file for the main activity. SkeletonAppActivity was in a different package from the application class. Good luck!

Make sure that android:hasCode is not set to false in your manifest file. This is what solved the problem for me!

Well you have a java.lang.ClassNotFoundException. That means a class is missing in the application runtime. You should check wheather you have added all your libs to the build path.

Right click on your project -> properties -> java build path -> libraries, add your libs or create one containing your classes and enable order export for your libs.

In my case, the icon of the app was causing the error:

<application
    android:name="com.test.MyApp"
    android:icon="@drawable/myicon"
    

Why? Because I put the icon only in the folder "drawable", and I'm using a high resolution testing device, so it looks in the folder "drawable-hdpi" for the icon. The default behaviour for everything else is use the icons from "drawable" if they aren't in "drawable-hdpi". But for the launching icon this doesn't seem to be valid.

So the solution is to put a copy of the icon (with the same name, of course) in "drawable-hdpi" (or whichever supported resolutions the devices have).

I used a supertype method that was declared 'final' in one of my Activities (specifically the 'isResumed()' method). The actual error showed in LogCat only after restarting my development device.

The Class Not Found Error shows that your class files are missing. Please go to Properties > Java Build Path and add your package containing your java files to the Source tab if found missing. Then build your project. This will create the missing .class files.

I recently invested some time in a similar error report that reached me through the play store error reports.

An overview of some possible causes.

Missing Library

Since my app is tested before release and the issue only occurs approx. once a week I'm pretty sure mine isn’t a library issue. You should think in this direction if a build on your system fails and installing the app using ADB results in error on launch.

Cleaning and building your project could help if this is a local issue and make sure you have the latest version of both SDK and IDE.

In these cases it’s one class of your app or a library used in your app that triggers the error. This is an important difference with the next point where the entry point (Activity with MAIN intent or your custom service/Application object) of your app is not found.

If so look into the following questions & answers I’ve selected. They all have an accepted answer.

https://stackoverflow.com/questions/17965707/unable-to-instantiate-application-classnotfoundexception https://stackoverflow.com/questions/10866431/android-activity-classnotfoundexception-tried-everything https://stackoverflow.com/questions/4880489/android-classnotfoundexception

Main Activity or Application not found

Misconfiguration of AndroidManifest.xml

More like a beginners mistake was quoted here before in one of the answers talking about the android manifest file.

Important here is that this error would always block your app from loading. It should build though but crash on the first use.

I’ve edited that answer, this is the important part:

> Do not use the android:name attribute! unless you've implemented a > custom Application object. > > The application:name attribute has nothing to do with the name of your > app. This is the name of a specific class to load as your Application > instance. That's why you would get the ClassNotFoundException if that > class wouldn't exist. > > For the name of the app use the android:label attribute on this same > application node instead.

Suppressed: java.io.IOException: unable to open DEX file

Now it’s getting interesting! This was part of the stack trace logged in my case through the playstore. So I can create a build and execute that on my device without errors (whereas all previous errors would prevent any run).

An important comment was made to the following SO question https://stackoverflow.com/questions/22057555/android-application-classnotfoundexception-unable-to-instantiate-application

> Looks like the system has trouble opening your application dex file java.io.IOException: unable to open DEX file, this is before any of your classes are loaded, so it doesn't have anything to do with how you define your application class in the Manifest. – user2046264 Feb 27 '14 at 2:25

The important part here is the suppressed IOException. This indicates that an IO operation failed. Examples of IO operations are network and storage calls.

Another error report that goes into that direction is listed at https://stackoverflow.com/questions/10311537/android-to-unable-to-instantiate-application-java-lang-classnotfoundexception where the role of the external storage provided by an sdcard is mentioned.

> Some other similar questions indicate that this can be a user error. "/mnt/asec/..." indicates that the app is running from the sdcard. If the sdcard is removed it could cause this error. 3rd party apps or rooted devices can probably move an app to the sdcard even if its not allowed by the manifest.

If you’re desperate read all the answers to that question since there are some other paths listed also. Think of full package specification, use of singletons and more.

The point here is that both network and storage are IO.

For my specific case I checked all the devices that reported this error and found that they all have external storage support. So a user could install the app and move it to external storage, have the SD card removed and get this error (just a theory, not tested).

For more info on the installLocation options see http://developer.android.com/guide/topics/data/install-location.html

I also considered the network. On top of the stack trace detail page at the play store reports you get an overview of the occurrences of the error over time.

It appeared to me that the error occurred more around the times an update was released. This could support the theory that the user gets an update of the app, downloads this update that somehow gets corrupted. The installation goes fine but the first execution of the app results in the error (again just a theory, not tested).

Other resources

Finally 2 non SO resources that might help you:

https://groups.google.com/forum/#!topic/android-developers/JC7_qqwBRjo https://code.google.com/p/android/issues/detail?id=72121

Are you using your code in different enviroments, let's say, by using Dropbox or something like that? Do you use any library or similar? I had a lot of troubles after sharing the workspace files and I fixed it reconfiguring dependences. Hope it helps somebody!

Check if the package name in the class matches the package name in the manifest file. This worked for me

In my case it happen when i moved my launcher activity to different package without updating manifest file.

I had a ClassNotFoundException pointing to my Application class.

I found that I missed Java builder in my .project

If something is missing in your buildSpec, close Eclipse, make sure everything is in place and start Eclipse again

        <buildSpec>
            <buildCommand>
                    <name>com.android.ide.eclipse.adt.ResourceManagerBuilder</name>
                    <arguments>
                    </arguments>
            </buildCommand>
            <buildCommand>
                    <name>com.android.ide.eclipse.adt.PreCompilerBuilder</name>
                    <arguments>
                    </arguments>
            </buildCommand>
            <buildCommand>
                    <name>org.eclipse.jdt.core.javabuilder</name>
                    <arguments>
                    </arguments>
            </buildCommand>
            <buildCommand>
                    <name>com.android.ide.eclipse.adt.ApkBuilder</name>
                    <arguments>
                    </arguments>
            </buildCommand>
    </buildSpec>

I have same problem in android os version 4.1.2

add below line to your AndroidManifest.xml below android:label="@string/app_name" in application tag

android:name="android.support.multidex.MultiDexApplication"

This may help some one with same problem.

Setting minifyEnabled to false in my build.gradle file fixed the issue for me.

release {
    minifyEnabled false
}

For me it was just to clean project.

I cleaned project, and run again. And all errors gone.

What helped me in case of Android Studio: The problem occurred after renamning package of large project. So I did almost everything AS offers to clean and refresh the project officially, and it works. I'm not saying this is solution for everyone just in case you're using Android Studio. Done in Android Studio 3.5.1, Windows 10.

• Alex's answer
• Build > Clean Project
• Build > Rebuild Project
• File > Sync with File System
• File > Sync project with Gradle Files
• File > Invalidate Caches / Restart

Make sure that you have package

com.aaraf.demowithdoc //Your Package Name 

com.aaraf.demowithdoc [YOUR PACKAGE NAME] is there in your class where this java.lang.classnotfoundexception is occuring

For me, 'closing' the application from Eclipse and 'reopening' of the project, resolved the issue.