Failed to compile resources with the following parameters:
-bootclasspath "C:/Program Files/Android\platforms\android-25\android.jar" -d "C:\Users\jordan\Desktop\GCSE Book Review\Temp\StagingArea\bin\classes" -source 1.6 -target 1.6 -encoding UTF-8 "com\jordna\GCSEBookReview\R.java" "com\unity3d\ads\R.java"
warning: C:\Program Files\Android\platforms\android-25\android.jar(java/lang/Object.class): major version 52 is newer than 51, the highest major version supported by this compiler.
  It is recommended that the compiler be upgraded.
warning: C:\Program Files\Android\platforms\android-25\android.jar(java/lang/AutoCloseable.class): major version 52 is newer than 51, the highest major version supported by this compiler.
  It is recommended that the compiler be upgraded.
2 warnings

UnityEditor.HostView:OnGUI()