Mongodb QueryByExample findOne

Some other process inserts documents into mongo collection and below is the sample data

{ "_id" : ObjectId("597b89c8da52380b04ee6948"), "_class" : "com.test.mongo", "clientId" : "CAQ123999", "isValid" : false, "isParent" : true }
{ "_id" : ObjectId("597b89c8da52380b04ee6949"), "_class" : "com.test.mongo", "clientId" : "CAQ123999", "isValid" : false, "isParent" : true }
{ "_id" : ObjectId("597b89c8da52380b04ee6950"), "_class" : "com.test.mongo", "clientId" : "CAQ123998", "isValid" : true, "isParent" : true }
{ "_id" : ObjectId("597b89c8da52380b04ee6951"), "_class" : "com.test.mongo", "clientId" : "CAQ123997", "isValid" : true, "isParent" : false }

I'm trying to grab one record for the clientId, using QueryByExampleExecutor.

Here is my model

package com.test.cfp.model;
public class TFSModel {

    private String clientId;
    private boolean isValid;
    private boolean isParent;
    ...

}

Here is the code to build the example:

TFSModel tfs = new TFSModel();
            tfs.setClientId(CAQ123999);
            tfs.setValid(false);
            tfs.setParent(true);    
            ExampleMatcher matcher =ExampleMatcher.matching().withIgnoreNullValues().withIgnorePaths("_id","_class");
            Example<TFSModel > example = Example.of(tfs,matcher);           
            TFSModel oneTfsRecord  = tflsRepository.findOne(example);

This is not working , below is the generated query

findOne using query: { "isValid" : false , "isParent" : true , "clientId" : "CAQ123999" , "_class" : { "$in" : [ "com.test.cfp.model.TFSModel"]}} in db.collection: returns.tfs;

Obviously the _class has the different package than the one in the mongo collection. How can I tell mongo to build a query without _class. I tried withIgnoredPaths and its not working.