How to use a for loop on database entity using netbeans IDE and EJB?

i has created this method the idea is to set the state from each member on the database when res is after the date or before the date, my question is wich is the correct way to apply a for loop so i can update the state for each person in my DB

  public String updateState(){
    if (date.compareTo(res.getDateLate())<0){
        person.setState("Active");
    return "List";
                } else { 
                person.setState("Inactive");
                return "List";
                       }                     
                                    }

Aditional info: I am running netbeans IDE