java.lang.RuntimeException: Fail to connect to camera service
	at android.hardware.Camera.<init>(Camera.java:704)
	at android.hardware.Camera.open(Camera.java:539)
	at com.google.android.gms.vision.a.j(SourceFile)
	at com.google.android.gms.vision.a.d(SourceFile)
	at com.entitcs.office_attendance.camera.CameraSourcePreview.f(SourceFile)
	at com.entitcs.office_attendance.camera.CameraSourcePreview.b(SourceFile)
	at com.entitcs.office_attendance.camera.CameraSourcePreview$b.surfaceCreated(SourceFile)
	at android.view.SurfaceView.updateWindow(SurfaceView.java:712)
	at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:183)
	at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:944)
	at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2574)
	at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1479)
	at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7019)
	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:907)
	at android.view.Choreographer.doCallbacks(Choreographer.java:709)
	at android.view.Choreographer.doFrame(Choreographer.java:644)
	at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:893)
	at android.os.Handler.handleCallback(Handler.java:836)
	at android.os.Handler.dispatchMessage(Handler.java:103)
	at android.os.Looper.loop(Looper.java:203)
	at android.app.ActivityThread.main(ActivityThread.java:6269)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)