code: @Override
    public void readSessionData() {
      this.dispatcher.execute(this.userService.isCurrentUserLoggedIn(),
          new AbstractSimpleRestCallback<GwtpSpringSession<T>, Boolean, HttpMessages>(this, this) {
  
            @Override
            public void onSuccess(final Boolean presult) {
              if (BooleanUtils.isTrue(presult)) {
                // we do have a logged in user, read it
                GwtpSpringSession.this.dispatcher.execute(
                    GwtpSpringSession.this.userService.getCurrentUser(),
                    new AbstractSimpleRestCallback<GwtpSpringSession<T>, T, HttpMessages>(
                        GwtpSpringSession.this, GwtpSpringSession.this) {
  
                      @Override
                      public void onSuccess(final T presult) {
                        GwtpSpringSession.this.setUser(presult);
                      }
                    });
              } else {
                GwtpSpringSession.this.setUser(null);
              }
            }
  
          });
    }
docs: read session data.