When I upgraded my project Android Studio 2.0 (which triggered me to upgrade com.android.tools.build:gradle:1.50 to com.android.tools.build:gradle:2.0), I get the following error:
Error:objc[17636]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/bin/java and /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/jre/lib/libinstrument.dylib. One of the two will be used. Which one is undefined.
The error seems to be benign and I tried some of the suggestions at https://code.google.com/p/android/issues/detail?id=204797 and it did not seem to help.
I've also seen numerous reports of this being a JDK issue here (which has not fixed yet), but it's odd that this only happens after I upgraded the gradle version.