Object stored as binary insteed of json

I am using ‘MappingCouchbaseConverter’ from spring library like below

CouchbaseDocument target = new CouchbaseDocument();
mappingCouchbaseConverter.write(myObject, target);
ctx.insert(couchbaseClientFactory.getCollection(
“mybucketName”).reactive(), null, target.getContent());

I am using transactions.

above code writes a binary data insteed of JSON, can anyone please help, how can I write the Json insteed of binary object