driver-legacy/src/main/com/mongodb/BulkWriteOperation.java
public BulkWriteResult execute() {
        isTrue("already executed", !closed);
        closed = true;
        return collection.executeBulkWriteOperation(ordered, bypassDocumentValidation, requests);
    }
public BulkWriteResult execute() {
        isTrue("already executed", !closed);
        closed = true;
        return collection.executeBulkWriteOperation(ordered, bypassDocumentValidation, requests);
    }
Execute the bulk write operation with the default write concern of the collection from which this came.  Note that the
continueOnError property of the write concern is ignored.

@return the result of the bulk write operation.
@throws com.mongodb.BulkWriteException if the write failed due some other failure specific to the write command
@throws MongoException if the operation failed for some other reason