"Failed to recompile android resource files" after adding Unity Ads

Hello!

I've added Unity Ads using this tutorial

It showed the ads (testing turned on) in the Game View and basically everything worked well.
But after building I got this message "Failed to recompile android resource files. See the console for details.".

So I tried to add Unity Ads using a more professional tutorial made by Unity

And I get the same error.

Before these Ads, I could build without any error.

These are the console messages:

CommandInvokationFailure: Failed to recompile android resource files. See the Console for details.
E:\Java\bin\javac.exe -bootclasspath "C:/Users/Cristi/AppData/Local/Android/sdk\platforms\android-23\android.jar" -d "E:\Rolling\Rolling\Temp\StagingArea\bin\classes" -source 1.6 -target 1.6 -encoding UTF-8 "com\cizmar\tdba\R.java" "com\unity3d\ads\android\R.java"
stderr[
Error: Could not find or load main class com.sun.tools.javac.Main
]
stdout[
]
UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.PostProcessAndroidPlayer.Exec (System.String command, System.String args, System.String workingdir, System.String[] progress_strings, Single progress_value, System.String errorMsg)
UnityEditor.Android.PostProcessAndroidPlayer.CompileResources (System.String stagingArea, System.String packageName, UnityEditor.Android.AndroidLibraries androidLibraries)
UnityEditor.Android.PostProcessAndroidPlayer.PostProcessInternal (System.String stagingAreaData, System.String stagingArea, System.String playerPackage, System.String installPath, System.String companyName, System.String productName, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry)
UnityEditor.Android.PostProcessAndroidPlayer.PostProcess (BuildTarget target, System.String stagingAreaData, System.String stagingArea, System.String playerPackage, System.String installPath, System.String companyName, System.String productName, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry)
UnityEditor.HostView:OnGUI()

and

Error building Player: CommandInvokationFailure: Failed to recompile android resource files. See the Console for details.
E:\Java\bin\javac.exe -bootclasspath "C:/Users/Cristi/AppData/Local/Android/sdk\platforms\android-23\android.jar" -d "E:\Rolling\Rolling\Temp\StagingArea\bin\classes" -source 1.6 -target 1.6 -encoding UTF-8 "com\cizmar\tdba\R.java" "com\unity3d\ads\android\R.java"
stderr[
Error: Could not find or load main class com.sun.tools.javac.Main
]
stdout[
]

Can somebody help me?

 

Problem was a bad JAVA_HOME path value...

 

Could you elaborate?