java lang ClassNotFoundException on working app

Question

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

User · Answer

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.

unable to instantiate application - ClassNotFoundException Android Activity ClassNotFoundException - tried everything 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 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 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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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    If the package name is com test then activities names should be  ActivityName  with a leading dot   not just ActivityName  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

User · Answer

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  lt methods gt      -keepclasseswithmembers class         public  lt init gt  android content Context  android util AttributeSet      -keepclasseswithmembers class         public  lt init gt  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

User · Answer

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

User · Answer

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           lt buildSpec gt               lt buildCommand gt                       lt name gt com android ide eclipse adt ResourceManagerBuilder lt  name gt                       lt arguments gt                       lt  arguments gt               lt  buildCommand gt               lt buildCommand gt                       lt name gt com android ide eclipse adt PreCompilerBuilder lt  name gt                       lt arguments gt                       lt  arguments gt               lt  buildCommand gt               lt buildCommand gt                       lt name gt org eclipse jdt core javabuilder lt  name gt                       lt arguments gt                       lt  arguments gt               lt  buildCommand gt               lt buildCommand gt                       lt name gt com android ide eclipse adt ApkBuilder lt  name gt                       lt arguments gt                       lt  arguments gt               lt  buildCommand gt       lt  buildSpec gt

User · Answer

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      lt application         android name  quot Novak ESC Track guide quot          android icon  quot  drawable icon quot          android label  quot  string app name quot          android description  quot  string help text quot   gt   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   lt application      android icon  quot  drawable icon quot       android label  quot  string app name quot       android description  quot  string help text quot   gt

User · Answer

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

User · Answer

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  -

User · Answer

For me it was just to clean project    I cleaned project  and run again  And all errors gone

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

I got this error when I ran my app on earlier versions of android   I thought SearchView was backwards compatible to Android 1 5  but it was created in 3 0   I removed its reference from the code and it worked

User · Answer

In my case  the icon of the app was causing the error    lt 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

User · Answer

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

User · Answer

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

User · Answer

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    Android Private Libraries - checked Android 4 2 2 - unchecked Android Dependencies - checked  src - selected  gen - selected   It resolved the issue  Hope this is Help you guys

User · Answer

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

[android] java.lang.ClassNotFoundException on working app

Missing Library

Main Activity or Application not found

Misconfiguration of AndroidManifest.xml

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

Other resources

Examples related to android

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