Java API Concurrency with multiple users accessing app.

Thanks for clarifying. The API was designed with the intention that each user would link their own Dropbox account, in order to interact with their own files. However, it is technically possible to connect to just one account. The SDKs don't offer explicit support for it and we don't recommend doing so, for various technical and security reasons.

However if you did want to go this route, instead of kicking off the authorization flow, you would manually use an existing access token for your account and app. (Just be careful not to revoke it, e.g. via https://www.dropbox.com/account/security .)

In any case, the Dropbox API doesn't offer any sort of file locking, so there isn't a good way to manage this, but I'll be sure to pass this along as feedback. (The mention of leases in the webhooks documentation was in reference to hypothetical leasing you could build into your app's own code when handling changes, not about making calls to the Dropbox API.)

Anyway, for handling how files are uploaded, and how to prevent and manage conflicts, you should read about the different write modes available. E.g., if you're using the Java Core SDK:

https://dropbox.github.io/dropbox-sdk-java/api-docs/v1.8.x/com/dropbox/core/DbxWriteMode.html