Sometimes depends on libraries that you have used in your Android project this annoying error shows up during gradle build using Android Studio:
Error:com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK META-INF/LICENSE.txt
can be solve this issue and many more by adding this to the Android tag of your build.grade file:
packagingOptions { exclude 'META-INF/DEPENDENCIES.txt' exclude 'META-INF/LICENSE.txt' exclude 'META-INF/NOTICE.txt' exclude 'META-INF/NOTICE' exclude 'META-INF/LICENSE' exclude 'META-INF/DEPENDENCIES' exclude 'META-INF/notice.txt' exclude 'META-INF/license.txt' exclude 'META-INF/dependencies.txt' exclude 'META-INF/LGPL2.1' }