Execution failed with backendless: Please solve this problem quick

Error:Execution failed for task ‘:app:transformResourcesWithMergeJavaResForDebug’. > com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK weborb.tasks File1: E:\androidAPPS\NearBY\app\libs\backendless.jar File2: C:\Users\RAHUL.gradle\caches\modules-2\files-2.1\com.backendless\backendless\3.0.11\fbdf1b3f7412ec5029822879e19e1031008cb4f9\backendless-3.0.11.jar

Whole message:

Information:Gradle tasks [:app:clean, :app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:assembleDebug]
:app:clean
:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72311Library
:app:prepareComAndroidSupportDesign2311Library
:app:prepareComAndroidSupportMediarouterV72300Library
:app:prepareComAndroidSupportMultidex101Library
:app:prepareComAndroidSupportRecyclerviewV72311Library
:app:prepareComAndroidSupportSupportV42311Library
:app:prepareComGoogleAndroidGmsPlayServices840Library
:app:prepareComGoogleAndroidGmsPlayServicesAds840Library
:app:prepareComGoogleAndroidGmsPlayServicesAnalytics840Library
:app:prepareComGoogleAndroidGmsPlayServicesAppindexing840Library
:app:prepareComGoogleAndroidGmsPlayServicesAppinvite840Library
:app:prepareComGoogleAndroidGmsPlayServicesAppstate840Library
:app:prepareComGoogleAndroidGmsPlayServicesAuth840Library
:app:prepareComGoogleAndroidGmsPlayServicesBase840Library
:app:prepareComGoogleAndroidGmsPlayServicesBasement840Library
:app:prepareComGoogleAndroidGmsPlayServicesCast840Library
:app:prepareComGoogleAndroidGmsPlayServicesDrive840Library
:app:prepareComGoogleAndroidGmsPlayServicesFitness840Library
:app:prepareComGoogleAndroidGmsPlayServicesGames840Library
:app:prepareComGoogleAndroidGmsPlayServicesGcm840Library
:app:prepareComGoogleAndroidGmsPlayServicesIdentity840Library
:app:prepareComGoogleAndroidGmsPlayServicesLocation840Library
:app:prepareComGoogleAndroidGmsPlayServicesMaps840Library
:app:prepareComGoogleAndroidGmsPlayServicesMeasurement840Library
:app:prepareComGoogleAndroidGmsPlayServicesNearby840Library
:app:prepareComGoogleAndroidGmsPlayServicesPanorama840Library
:app:prepareComGoogleAndroidGmsPlayServicesPlus840Library
:app:prepareComGoogleAndroidGmsPlayServicesSafetynet840Library
:app:prepareComGoogleAndroidGmsPlayServicesVision840Library
:app:prepareComGoogleAndroidGmsPlayServicesWallet840Library
:app:prepareComGoogleAndroidGmsPlayServicesWearable840Library
:app:prepareDebugDependencies
:app:compileDebugAidl
:app:compileDebugRenderscript
:app:generateDebugBuildConfig
:app:generateDebugAssets UP-TO-DATE
:app:mergeDebugAssets
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources
:app:mergeDebugResources
:app:processDebugManifest
:app:processDebugResources
:app:generateDebugSources
:app:preDebugAndroidTestBuild UP-TO-DATE
:app:prepareComAndroidSupportMultidexInstrumentation101Library
:app:prepareDebugAndroidTestDependencies
:app:compileDebugAndroidTestAidl
:app:processDebugAndroidTestManifest
:app:compileDebugAndroidTestRenderscript
:app:generateDebugAndroidTestBuildConfig
:app:generateDebugAndroidTestAssets UP-TO-DATE
:app:mergeDebugAndroidTestAssets
:app:generateDebugAndroidTestResValues UP-TO-DATE
:app:generateDebugAndroidTestResources
:app:mergeDebugAndroidTestResources
:app:processDebugAndroidTestResources
:app:generateDebugAndroidTestSources
:app:mockableAndroidJar UP-TO-DATE
:app:preDebugUnitTestBuild UP-TO-DATE
:app:prepareDebugUnitTestDependencies
:app:compileDebugJavaWithJavac
:app:compileDebugNdk UP-TO-DATE
:app:compileDebugSources
:app:buildInfoDebugLoader
:app:transformClassesWithExtractJarsForDebug
:app:transformClassesWithInstantRunVerifierForDebug
:app:transformClassesWithJavaResourcesVerifierForDebug
:app:mergeDebugJniLibFolders
:app:transformNative_libsWithMergeJniLibsForDebug
:app:processDebugJavaRes UP-TO-DATE
:app:transformResourcesWithMergeJavaResForDebug FAILED
Error:Execution failed for task ‘:app:transformResourcesWithMergeJavaResForDebug’.

com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK weborb.tasks
File1: E:\androidAPPS\NearBY\app\libs\backendless.jar
File2: C:\Users\RAHUL.gradle\caches\modules-2\files-2.1\com.backendless\backendless\3.0.11\fbdf1b3f7412ec5029822879e19e1031008cb4f9\backendless-3.0.11.jar
Information:BUILD FAILED
Information:Total time: 26.334 secs
Information:1 error
Information:0 warnings
Information:See complete output in console

Anyone solve this problem please.

Hi, Rahul.

It is hard to understand your problem by the stacktrace only. In order to reproduce this error you could send us your project at support@backendless.com.
Some additional information would be also helpful:
After what changes did you start to get this error?
Did the project work without errors before?

its working now.

how did you fixed it ?

Rahul, How did you fix the problem with “Duplicate files copied in APK weborb.tasks”

The solution is simple , juste go into your project folder and delete the folder .gradle and try to complie the project again

I had the same issue. It was result of have Backendless 3 as .jar file(I was using it as part of one of my libraries) and Backendless 4 referenced in gradle file. The solution was:
1.-Delete Backend 3
2.-Recode all issues from Backend 3 to 4
3.-Delete .gradle folder from proyect
4.-In Android Studio select File>Invalidate caches and restart
5.-Rebuilt project

I hope this helps