$lookup and aggregation in MongoDB and Spring-data

Question

I have this $lookup operation and I have implemented it with Spring. My problem is, that when I am running it in a shell it's working fine but with Spring it's not working. The interesting part is, that when I am adding a $match into Spring (where I have implemented it), it's working. But I don't need $match I just need simple $lookup without $match. Please help me.
Thanks in Advance.

Mongo-Query :

db.twitterconnection.aggregate([   
    { "$lookup": {
       "from": "twitteruser",
       "localField": "connection_id",
       "foreignField": "user_id",
       "as": "followers"
    }}
]);

Spring Implementation:

public  List <TwitterResult> lookupOperation(){
    LookupOperation lookupOperation = LookupOperation.newLookup()
                        .from("twitteruser")
                        .localField("connection_id")
                        .foreignField("user_id")
                        .as("followers");

    //Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(Criteria.where("user_id").is("1")) , lookupOperation);//If I use this then it's working fine. 
    Aggregation aggregation = Aggregation.newAggregation(lookupOperation);
    List<TwitterResult> results = (List<TwitterResult>) mongoTemplate.aggregate(aggregation, "twitterconnection", TwitterResult.class).getMappedResults();
    System.out.println("Obj Size " +results.size());
    System.out.println(" Results : "+results.toString());

return results;
}