There is one approach mentioned in http://www.vogella.com/tutorials/Dagger/article.html#connecting-consumers-and-providers and other approch without using Component here http://antonioleiva.com/dagger-android-part-2/.
First, please note that Dagger 2 and Dagger are not the same thing. If you read
ObjectGraph you are probably reading about Dagger (1).
You can not use Dagger 2 without components. Components are the objects that hold your dependencies and know how to provide and inject them. I think the same holds true for Dagger 1 about their ObjectGraph. If you don't have the means to provide your dependencies, you can't use DI.