Use WriteConcern in MongoCollection.deleteMany in mongo-java-driver 3.12

Question

I am using mongo-java-driver-3.12.X version. I want to change the deprecated API

DBCollection.remove(query, WriteConcern.UNACKNOWLEDGED);

to

MongoCollection.deleteMany(query)

1. Is there a way to specify WriteConcern?
2. What will be the default behaviour if WriteConcern is not specified?

Answer 1

You can easily find this information in the driver documentation.

WriteConcern can be set to multiple level for 3.12 version it goes like this.

MongoClient:

MongoClientOptions options = MongoClientOptions.builder().writeConcern(WriteConcern.UNACKNOWLEDGED).build();
MongoClient mongoClient = new MongoClient(Arrays.asList(
        new ServerAddress("host1", 27017),
        new ServerAddress("host1", 27018)), options);

or with a connection string

MongoClient mongoClient = new MongoClient(new MongoClientURI("mongodb://host1:27017,host2:27017/?w=unacknowledged"));

MongoDatabase

MongoDatabase database = mongoClient.getDatabase("test").withWriteConcern(WriteConcern.UNACKNOWLEDGED);

MongoCollection

This is the case you are interested in

MongoCollection<Document> collection = database.getCollection("restaurants").withWriteConcern(WriteConcern.UNACKNOWLEDGED);
collection.deleteMany(query);

Keep in mind that MongoCollection and MongoDatabase are immutable so calling withWriteConcern create a new instance and has no effect on the original instance.

For the default behavior you need to check the documentation because it depends on your mongodb version.