Auto authorize with Java client or Mule ESB component

The tutorial shows how to go through the auth flow in a command-line app (https://www.dropbox.com/developers/core/start/java), and as it says, you can just store the access token for future use:

The access token is all you'll need to make API requests on behalf of this user, so you should store it away for safe-keeping (even though we don't for this tutorial). By storing the access token, you won't need to go through these steps again unless the user reinstalls your app or revokes access via the Dropbox website.

If you just need an access token for your own account—no other user will use your app—you can generate an access token directly from the app console: https://blogs.dropbox.com/developers/2014/05/generate-an-access-token-for-your-own-account/.