Pfthb

I have a document stored in Couchbase.

 "a": 
 "b": 
 "key":"Value"
 ,
 "_class":"com.nikhil.model"
 ,
 "c":
 "d":
 "key":"value"
 ,
 // _class is missing here
 ,
 "_class": "com.nikhil.model"
 

Here as you can see I don't have an _class inside the "d" in the doucument because of this I am not able to get this document. An object mapping exception came.
_class is used to map the nested object of couchbase to the model required for mapping but inside the "c" object I don't have this _Class property that is why a mapping exception comes.
Is there any fix for this?

If you are using Spring boot, you need to override the typekey() method in the Couchbase Config file which extends AbstractCouchbaseConfiguration and return MappingCouchbaseConverter.TYPEKEY_SYNCGATEWAY_COMPATIBLE. This will replace your _class with javaClass string in the documents stored in Couchbase Server. I hope this helps.

@Configuration
public class RemoteCouchbaseConfiguration extends AbstractCouchbaseConfiguration 

 @Value("$couchbase.host")
 private String host;

 @Value("$couchbase.bucket.bucketName")
 private String bucketName;

 @Value("$couchbase.bucket.password")
 private String password;

 @Override
 protected List<String> getBootstrapHosts() 
 return Arrays.asList(this.host);
 

 @Override
 protected String getBucketName() 
 return this.bucketName;
 

 @Override
 protected String getBucketPassword() 
 return this.password;
 

 @Override
 public String typeKey() 
 return MappingCouchbaseConverter.TYPEKEY_SYNCGATEWAY_COMPATIBLE;
 

Looks like you are using Couchbase with Spring Data, the easiest way is to return a projection:

@Override
public List<UserVO> getUsers(String companyId, List<String> userIds) 

 String queryString = "SELECT meta(t).id as id, t.login as login, t.firstName as firstName from " + getBucketName() + " t where t."+getClassFilter()+" "
 + " and t.companyId = '" + companyId + "' and t.isEnabled = true and t.isVisible = true "
 + " and meta(t).id in ["+userIds.stream().map(e->"'"+e+"'").collect( Collectors.joining( "," )) +"]";
 N1qlParams params = N1qlParams.build().consistency(ScanConsistency.NOT_BOUNDED).adhoc(true);
 ParameterizedN1qlQuery query = N1qlQuery.parameterized(queryString, JsonObject.create(), params);

 return userRepository.getCouchbaseOperations().findByN1QLProjection(query, UserVO.class);

You could add _class to it using an UPDATE N1QL statement like this:

UPDATE mybucket b
SET b.c.d._class = 'com.foo.bar'
WHERE b.c.d IS NOT MISSING
AND b.c.d._class IS MISSING

That will update any document that has a 'd' object within a 'c' object but doesn't have a '_class' within the c object.