Spring Data mongo to insert null values to DB

NoSQL DB works in a different way compared to RDBMS. the document {"age":21,"name":"john Doe"} is same as {"age":21,"name":"john Doe";"address":null}

instead of storing the key's as null better to not store the key at all this improves the performance of your reads/updates against the DB. However, if your usecase still demands to sore null due to whatever the reasons it might be convert your POJO to BSONObject and then persist the BSONObject in the MongoDB.

Here is the example ( but however it will be only a work around to get the things going)

BSONObject personBsonObj = BasicDBObjectBuilder.start()
                .add("name","John Doe")
                .add("age",21)
                .add("address",null).get();


 if you are using spring data mongo use

mongoTemplate.insert(personBsonObj,"personCollection");
document in the db:
db.personCollection.findOne().pretty();
{"age":21,"name":"John Doe";"address":null}*