Working with the Collections Developer Preview
Collections is introduced as a Developer Preview feature in Couchbase Server 6.5. The 3.0 API SDKs all work with Collections and Scopes.
The Developer Preview of the upcoming Collections feature in Couchbase Server is fully implemented in the 3.0 API versions of the Couchbase SDKs.
When working without the DP implemented, or with other server versions, the
defaultcollection is used from the SDK.