I have a collection in MongoDB called 'customers' where I store documents with different schemas.

In my Spring Boot Application I have the following Repository:

public interface BgradeCustomerRepository extends MongoRepository<BgradeCustomer, String> {
    public List<BgradeCustomer> findByScoreExists(boolean exists);
} 

When I invoke findByScoreExists and pass true, it works fine and I get the collection of objects with property 'score', but the problem is when I pass false to findByScoreExists, I get the collection of 'BgradeCustomer' objects with only the common properties with the other schemas !!

I changed the method signature to be:

// Customer is the other schema in the collection 
public List<Customer> findByScoreExists(boolean exists);

but that never worked, I always get 'java.lang.NullPointerException: null'

So, how can I get all the objects that doesn't have a specific property ?