Failed to Compile resources with the following parameters?

Unity Engine
1

Hello,

I updated my sdk and now i get this error. I think i need to delete something but i don’t know what to delete to fix this situation.

Failed to compile resources with the following parameters:
-bootclasspath "/Users/username/adt-bundle-mac-x86_64-20140702/sdk/platforms/android-21/android.jar" -d "/Users/username/XXX/XXX/Project/ProjectFolder/Project/Project/Temp/StagingArea/bin/classes" -source 1.6 -target 1.6 -encoding UTF-8 "com/CompanyName/Project/R.java" "com/google/android/gms/R.java" "com/google/example/games/basegameutils/R.java" "com/google/example/games/mainlibproj/R.java"
warning: java/lang/Object.class(java/lang:Object.class): major version 51 is newer than 50, the highest major version supported by this compiler.
It is recommended that the compiler be upgraded.
1 warning

UnityEditor.HostView:OnGUI()
2

I deleted the sdk folder and redownloaded and updated it but i still get error when i want to build my project… My computer system is Mac. What could be the problem? I must update the sdk otherwise the project will not work on every version of android.

3

same problem. any solution?