The reason for the java wrap was to invoke either the Dropbox app or the web browser to do the authneticate.
Users were not comfortable entering their details in my app.
I think it depends on what you want to realize. As far as i see in the Dropbox SDK documentation you need an accesstoken to access data from "your dropbox".
So if we are talking about an app from you then your Dropbox account is used to retrieve/store files.
If you want to store a file from your dropbox down to the dropbox of someone else (like when clicking a share button in your app for ex.). Here is a http api
available for this too... but i did not tried it as yet. I see the api to be used by myself (in my apps) to store and retrieve files online when needed.
What exactly do you want to archieve?