can optional be use in merging maps in Java?

import java.util.Map;

class VisitCounter {

Map<Long, Long> count(Map<String, UserStats>... visits) {
    
    return null;
      
}

}

import java.util.Optional;

public class UserStats {

Long visitCount = null;

Optional<Long> getVisitCount() {
    return Optional.ofNullable(this.visitCount);
}

void setVisitCount(Long visitCount) {
    this.visitCount = visitCount;
}

}