Failed to compile to android (Unity)

Question

I am trying to compile my VR project to an android phone.

However i keep getting the following error:

Failed to compile resources with the following parameters:
-bootclasspath "C:/Program Files (x86)/Android/android-sdk\platforms\android-26\android.jar" -d "C:\Users\**\Documents\**\**\Temp\StagingArea\bin\classes" -source 1.6 -target 1.6 -encoding UTF-8 "com\google\gvr\keyboardsupport\R.java" "com\google\gvr\permissionsupport\R.java" "com\google\vr\cardboard\R.java" "com\google\vr\keyboard\R.java" "com\***\**\R.java" "com\unity3d\unitygvr\R.java"
warning: [options] source value 1.6 is obsolete and will be removed in a future release
warning: [options] target value 1.6 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.

I have installed Android Studio & the Android SDK i have also installed the newest version of Java SDK

Can anyone tell me what i can do?

More errrors:

    UnityException: Resource compilation failed!
Failed to recompile android resource files. See the Console for details.
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message, System.Exception ex)
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message)
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuildPointToConsole (System.String title, System.String message)
UnityEditor.Android.PostProcessor.Tasks.BuildResources.CompileResources (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.Tasks.BuildResources.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
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.BuildReporting.BuildReport report)
UnityEditor.Android.AndroidBuildPostprocessor.PostProcess (BuildPostProcessArgs args)
UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTargetGroup targetGroup, BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.BuildReporting.BuildReport report) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:263)
UnityEditor.HostView:OnGUI()

---

    UnityException: Resource compilation failed!
Failed to recompile android resource files. See the Console for details.
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message, System.Exception ex)
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message)
UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuildPointToConsole (System.String title, System.String message)
UnityEditor.Android.PostProcessor.Tasks.BuildResources.CompileResources (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.Tasks.BuildResources.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
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.BuildReporting.BuildReport report)
UnityEditor.Android.AndroidBuildPostprocessor.PostProcess (BuildPostProcessArgs args)
UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTargetGroup targetGroup, BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.BuildReporting.BuildReport report) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:263)
UnityEditor.HostView:OnGUI()

Answer 1

I think this is caused by JDK 9. I'm seeing this same error on my home computer, where I have JDK 9. I don't see the error at work, where I have JDK 8. (To be specific, I have this working using JDK 8 Update 131, 64 bit.)

If I'm reading the error message correctly, it looks like something in the unity or android toolchain is requesting source files be compiled targeting Java 6.0 (1.6). That's about 11 years old, and so has been marked as deprecated in JDK 9. Downgrading to JDK 8 should fix it for now. Eventually, that toolchain will need to be updated to support the newer version.