Complete log :

Error:Execution failed for task ':RDPDFReader:transformNative_libsWithStripDebugSymbolForDebug'.

> java.lang.NullPointerException (no error message) 

If you are facing this error RDPDFReader:transformNative_libsWithStripDebugSymbolForDebug , this article will help you.

This error seems to be related to some of your Android Studio settings.

We found some way to fix this problem, you can use one of these tips : 

      1. Go to local.properties file and comment the ndk line. (if you are not using ndk)

#ndk.dir=C\:\\Users\\Me\\AppData\\Local\\Android\\sdk\\ndk-bundle
sdk.dir=C\:\\Users\\Me\\AppData\\Local\\Android\\sdk

      2. Set both targetSdkVersion and compileSdkVersion to 22 (as written here http://stackoverflow.com/questions/39761895/errorexecution-failed-for-task-hello-motion-trackingtransformnative-libswith/40117446#40117446 )

      3. Downgrade android gradle plug-in version to 2.1.2 or 2.1.3 (as written here http://stackoverflow.com/a/40050992 )