code: static public void init(GVRContext gvrContext) throws JSONException,
              NoSuchMethodException {
          loadAnimations(gvrContext.getContext());
  
          gvrContext.runOnGlThread(new Runnable() {
              @Override
              public void run() {
                  sGLThread = new WeakReference<>(Thread.currentThread());
              }
          });
          GVRAssetLoader assetLoader = new GVRAssetLoader(gvrContext);
          sDefaultTexture = assetLoader.loadTexture(new GVRAndroidResource(
                  gvrContext, R.raw.default_bkgd));
          Log.d(TAG, "onInit(): default texture: %s", sDefaultTexture);
      }
docs: Call to initialize the Widget infrastructure. Parses {@code objects.json}
  to load metadata for {@code Widgets}, as well as animation and material
  specs.
  
  @param gvrContext
  A valid {@link GVRContext}.
  @throws JSONException
  if the {@code objects.json} file is invalid JSON
  @throws NoSuchMethodException
  if a constructor can't be found for an animation type
  specified in {@code objects.json}.