com.mongodb.MongoBulkWriteException: Bulk write operation error on server %mongohostport%. Write errors: [BulkWriteError{index=0, code=11000, message='E11000 duplicate key error collection: admin.coll index: _id_ dup key: { _id: "b" }', details={}}].
[ { "_id": "b", "name": "b" }, { "_id": "d", "name": "d" } ]