Error :: duplicate files during packaging of APK

I think you need to include only these options in build.gradle:

packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
    }

Add this in your build.gradle file ...

packagingOptions {
exclude 'META-INF/NOTICE' // will not include NOTICE file
exclude 'META-INF/LICENSE' // will not include LICENSE file
exclude 'META-INF/DEPENDENCIES' // will not include LICENSE file
exclude 'META-INF/LICENSE.txt'
exclude 'META-INF/NOTICE.txt'
}

like this...

android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
    applicationId "your package name"
    minSdkVersion 14
    targetSdkVersion 25
    versionCode 30
    versionName "3.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
packagingOptions {
    exclude 'META-INF/NOTICE' // will not include NOTICE file
    exclude 'META-INF/LICENSE' // will not include LICENSE file
    exclude 'META-INF/DEPENDENCIES' // will not include LICENSE file
    exclude 'META-INF/LICENSE.txt'
    exclude 'META-INF/NOTICE.txt'
}
}

I think the string comparison is case sensitive. try with exclude 'META-INF/notice.txt'

Short Answer:

See the detailed gradle output using gradle assemble and note the files that are duplicate and exclude them using:

android {
  packagingOptions {
    exclude 'META-INF/notice.txt'
  }
}

Long Answer:

Run the assemble gradle task from command line for detailed output:

./gradlew assemble || gradle assemble

This automatically shows what to exclude:

studioWorkspace/CCDroid git:(master) ✗ ± ./gradlew assembleDebug
:app:preBuild
:app:compileDebugNdk UP-TO-DATE
:app:preDebugBuild
:app:checkDebugManifest
:app:preReleaseBuild
:app:prepareComAndroidSupportAppcompatV72200Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42200Library UP-TO-DATE
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:generateDebugAssets UP-TO-DATE
:app:mergeDebugAssets UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources UP-TO-DATE
:app:processDebugManifest UP-TO-DATE
:app:processDebugResources UP-TO-DATE
:app:generateDebugSources UP-TO-DATE
:app:compileDebugJava UP-TO-DATE
:app:preDexDebug UP-TO-DATE
:app:dexDebug UP-TO-DATE
:app:processDebugJavaRes UP-TO-DATE
:app:validateDebugSigning
:app:packageDebug
Error: duplicate files during packaging of APK /Users/shubham/code/studioProjects/CCDroid/app/build/outputs/apk/app-debug-unaligned.apk
    Path in archive: LICENSE
    Origin 1: /Users/shubham/.gradle/caches/modules-2/files-2.1/org.projectlombok/lombok/1.14.8/8ac073941721e0b521ec8e8bad088b1e7b8cd332/lombok-1.14.8.jar
    Origin 2: /Users/shubham/.gradle/caches/modules-2/files-2.1/org.mockito/mockito-all/1.8.4/5c97d8b6e715ed941aeb93d6fc401ab3eb18a566/mockito-all-1.8.4.jar
You can ignore those files in your build.gradle:
    android {
      packagingOptions {
        exclude 'LICENSE'
      }
    }
:app:packageDebug FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:packageDebug'.
> Duplicate files copied in APK LICENSE
    File 1: /Users/shubham/.gradle/caches/modules-2/files-2.1/org.projectlombok/lombok/1.14.8/8ac073941721e0b521ec8e8bad088b1e7b8cd332/lombok-1.14.8.jar
    File 2: /Users/shubham/.gradle/caches/modules-2/files-2.1/org.projectlombok/lombok/1.14.8/8ac073941721e0b521ec8e8bad088b1e7b8cd332/lombok-1.14.8.jar


* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 11.863 secs

See this part in output:

android {
  packagingOptions {
    exclude 'LICENSE'
  }
}

It even shows the list of dependencies which originated duplicate files (LICENSE). See the lines with Origin # in the output.