import java.util.ArrayList; import java.util.List; import java.util.Map; public class SiteWrapper { private List<SiteA> sites = new ArrayList<>(); public void addSite(SiteA site) { sites.add(site); } public List<Map<String, Object>> getSiteValue() { List<Map<String, Object>> combinedList = new ArrayList<>(); for (SiteA site : sites) { combinedList.addAll(site.getValue()); } return combinedList; } }