add this into your build.gradle(module app)
android{ packagingOptions{ exclude 'AndroidManifest.xml' exclude 'lib/arm64-v8a/libcardioDecider.so' exclude 'lib/arm64-v8a/libcardioRecognizer.so' exclude 'lib/arm64-v8a/libcardioRecognizer_tegra2.so' exclude 'lib/arm64-v8a/libopencv_core.so' exclude 'lib/arm64-v8a/libopencv_imgproc.so' exclude 'lib/armeabi/libcardioDecider.so' exclude 'lib/armeabi-v7a/libcardioDecider.so' exclude 'lib/armeabi-v7a/libcardioRecognizer.so' exclude 'lib/armeabi-v7a/libcardioRecognizer_tegra2.so' exclude 'lib/armeabi-v7a/libopencv_core.so' exclude 'lib/armeabi-v7a/libopencv_imgproc.so' exclude 'lib/mips/libcardioDecider.so' exclude 'lib/x86/libcardioDecider.so' exclude 'lib/x86/libcardioRecognizer.so' exclude 'lib/x86/libcardioRecognizer_tegra2.so' exclude 'lib/x86/libopencv_core.so' exclude 'lib/x86/libopencv_imgproc.so' exclude 'lib/x86_64/libcardioDecider.so' exclude 'lib/x86_64/libcardioRecognizer.so' exclude 'lib/x86_64/libcardioRecognizer_tegra2.so' exclude 'lib/x86_64/libopencv_core.so' exclude 'lib/x86_64/libopencv_imgproc.so' } }
and add dependencies

dependencies { compile 'com.paypal.sdk:paypal-android-sdk:2.14.1' }
hope it will works for you

add this into your build.gradle (module app) file.
dependencies { compile 'com.paypal.sdk:paypal-android-sdk:2.14.1' }
don't add any jar file. and in same file add this
android{ packagingOptions{ exclude 'AndroidManifest.xml' exclude 'lib/arm64-v8a/libcardioDecider.so' exclude 'lib/arm64-v8a/libcardioRecognizer.so' exclude 'lib/arm64-v8a/libcardioRecognizer_tegra2.so' exclude 'lib/arm64-v8a/libopencv_core.so' exclude 'lib/arm64-v8a/libopencv_imgproc.so' exclude 'lib/armeabi/libcardioDecider.so' exclude 'lib/armeabi-v7a/libcardioDecider.so' exclude 'lib/armeabi-v7a/libcardioRecognizer.so' exclude 'lib/armeabi-v7a/libcardioRecognizer_tegra2.so' exclude 'lib/armeabi-v7a/libopencv_core.so' exclude 'lib/armeabi-v7a/libopencv_imgproc.so' exclude 'lib/mips/libcardioDecider.so' exclude 'lib/x86/libcardioDecider.so' exclude 'lib/x86/libcardioRecognizer.so' exclude 'lib/x86/libcardioRecognizer_tegra2.so' exclude 'lib/x86/libopencv_core.so' exclude 'lib/x86/libopencv_imgproc.so' exclude 'lib/x86_64/libcardioDecider.so' exclude 'lib/x86_64/libcardioRecognizer.so' exclude 'lib/x86_64/libcardioRecognizer_tegra2.so' exclude 'lib/x86_64/libopencv_core.so' exclude 'lib/x86_64/libopencv_imgproc.so' } }