Do drop box provide any api support by which I can create a new dropBox account using java.
The Dropbox API doesn't offer a general way to programmatically create accounts, but I'll be sure to pass this along as a feature request.
This is possible via Dropbox Business API apps though, which can create accounts in the process of adding members to teams, but that only applies to Business teams.
But in that case, as well user need to respond to the email and have to provide the login credentials. I am thinking of provisioning the user.