how to create Selective file Uploading feature in web application with Dropbox API

Dropbox does offer an API you can use for uploading and listing files, among other operations. You can find everything you need to get started with the Dropbox API, including documentation, tutorials, and SDKs here:

https://www.dropbox.com/developers

I recommend using one of the official SDKs, if possible, and following the respective tutorial to get started:

https://www.dropbox.com/developers/documentation

I also recommend reading the OAuth guide to understand how the authorization process works:

https://www.dropbox.com/developers/reference/oauth-guide

[Cross-linking for reference: https://stackoverflow.com/questions/53532632/java-web-project-integration-with-dropbox-api ]

It sounds like your question is about getting the input stream for a local file. This isn't directly related to Dropbox itself, so I'm afraid I can't be of much help with this. You may be better suited by referring to general Java IO documentation or guides for interacting with the local file system.

By the way, I redacted it from your post, but for the sake of security, you should disable that access token that you posted. You can do so by revoking access to the app entirely, if the access token is for your account, here:

https://www.dropbox.com/account/connected_apps

Or, you can disable just this access token using the API:

https://www.dropbox.com/developers/documentation/http/documentation#auth-token-revoke

You can do so in the Java SDK itself:

https://dropbox.github.io/dropbox-sdk-java/api-docs/v3.0.x/com/dropbox/core/v2/auth/DbxUserAuthRequests.html#tokenRevoke--

Or in the API v2 Explorer if you want:

https://dropbox.github.io/dropbox-api-v2-explorer/#auth_token/revoke