Gradle Build Failure
I also had this issue when upgrading everything that is built related to 23 (Android Libraries, SDK etc).
This proguard configuration fixed it for me:
-dontwarn org.apache.http.**-dontwarn android.net.http.AndroidHttpClient-dontwarn com.google.android.gms.**-dontwarn com.android.volley.toolbox.**
Turns out I had omitted the getDefaultProguardFile('proguard-android.txt')
line on the proguard files and was just using proguard-rules.pro
added these two line in progaurd
-dontwarn android.net.http.AndroidHttpClient-dontwarn com.google.android.gms.**
and it works..
It is related to library used in project.