Change WriteConcern.NONE to UNACKNOWLEDGED
Remove isNew() / notNew() method call on ObjectId
Change new Mongo() to new MongoClient()
Change DuplicateKey to DuplicateKeyException
Change collection.ensureIndex() to collection.createIndex()
Change DBRefBase to DBRef
Remove the use of the BSONByteBuffer
Remove the use of a protected deprecated field
Delete useless file
Remove call to a deprecated usage of new ObjectId()
remove isNew() / notNew() method call on ObjectId
Delete useless file