No it's not a successor to BDB. According to http://www.oracle.com/technetwork/database/nosqldb/learnmore... it's based on BDB-JE High Availability (HA). BDB-JE HA is a separate product that has been around for awhile. Basically it's a multiple node cluster where each node runs BDB-JE.
It sounds like they are just rebranding BDB-JE HA, adding a couple features, and calling it NoSQL.