Android Camera2 get camer id for front camera
CameraCharacteristics cameraCharacteristics = manager.getCameraCharacteristics(cameraId);
if (cameraCharacteristics == null)
throw new NullPointerException("No camera with id " + cameraId);
return cameraCharacteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT;