code: @CallSuper
      @Override
      protected void onSaveInstanceState(@NonNull Bundle outState) {
          super.onSaveInstanceState(outState);
          if (userCommentView != null && userCommentView.getText() != null) {
              outState.putString(STATE_COMMENT, userCommentView.getText().toString());
          }
          if (userEmailView != null && userEmailView.getText() != null) {
              outState.putString(STATE_EMAIL, userEmailView.getText().toString());
          }
      }
docs: /*
  (non-Javadoc)
  
  @see android.app.Activity#onSaveInstanceState(android.os.Bundle)