import java.util.ArrayList;
import java.util.List;

public class Client {
    Person p1=new Person("CRoach",19,1);
    Person p2=new Person("xiaoxian",20,2);
    Person p3=new Person("jiawei",20,3);
    Person p4=new Person("dameng",19,4);
    
    Environment environment=new Environment();
    SortByNamePositive sortByNamePositive=new SortByNamePositive();
    List<Person> list=new ArrayList<Person>();
    list.add(p1)；
}