code: @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
      @SuppressWarnings("ServiceCast")
      public static BluetoothAdapter getBluetoothAdapter(Context context) {
          return (BluetoothAdapter) context.getSystemService(Context.BLUETOOTH_SERVICE);
      }
docs: Get the {@link android.bluetooth.BluetoothAdapter} service for this context.
  @param context the context.
  @return the {@link android.bluetooth.BluetoothAdapter}