import java.util.*;class Person implements Comparable<Person>{   String name;   int age;   Person(){       name = "";	   age = 0;   }   Person(String name, int age){       this.name = name;	   this.age = age;   }   public String toString(){       return name + "...." + age;   }       public int compareTo(Person o){              if(name.compareTo(o.name)==0)	      return o.age - age;	   return o.name.compareTo(name);   }}class Student extends Person{     int score;	 public Student(){	     super();	 }	 public Student(String name, int age, int score){	     super(name, age);		 this.score = score;	 }	 	 public String toString(){	     return  name + "...." + age + "...." + "score: " + score;	 }}class Worker extends Person{     int salary;	 public Worker(){	     super();	 }	 public Worker(String name, int age, int salary){	     super(name, age);		 this.salary = salary;	 }	 	 public String toString(){	     return  name + "...." + age + "...." + "salary: " + salary;	 }}class ComparatorPerson implements Comparator<Person>{     public int compare(Person o1, Person o2){	     if(o1.name.compareTo(o2.name)==0)		    return o1.age - o2.age;		 return o1.name.compareTo(o2.name);	 }}     public class Test{   public static void main(String[] args){       ArrayList<Person> arr = new ArrayList<Person>();	   arr.add(new Person("hujunzheng", 22));	   arr.add(new Person("caihaibin", 21));	   arr.add(new Person("huangweidong", 22));	   	   ArrayList<Student> arr1 = new ArrayList<Student>();	   arr1.add(new Student("hujunzheng", 22, 500));	   arr1.add(new Student("caihaibin", 21, 444));	   arr1.add(new Student("huangweidong", 22, 777));	   	   ArrayList<Worker> arr2 = new ArrayList<Worker>();	   arr2.add(new Worker("789", 22, 500));	   arr2.add(new Worker("465", 21, 444));	   arr2.add(new Worker("798", 22, 777));	   	   //public boolean addAll(Collection<? extends E> c)// 泛型的上限：用于存储的数据	   // 如果不是<? extends E> 而只是<E> 那么E的子类型就不能加载进来！因为Collection<Person> 和 ArrayList<Student>泛型管理的不是同一数据类型	   // 而 <? extends E> 要求传进来的对象实例管理的泛型只要是 E 或者是 E的子类都行！	   arr.addAll(arr1);	   arr.addAll(arr2);	   	   Object[] oo = null;	   Arrays.sort(oo=arr.toArray());	   for(Object o : oo)	      System.out.println(o);		  	   //public TreeSet(Comparator<? super E> c); 传递的是比较泛型为 E 或者是 E的父类的比较器	   //在进行 E类型两个数据比较的时候， 用 E类 或者 E类型的父类型进行接收，并使用 ？类型的定义的比较方式！	   	   System.out.println("泛型上限，下限...................................................");	   TreeSet<Worker> tw = new TreeSet<Worker>(new ComparatorPerson());// E 是 Worker， 传递的是其父类Person的比较器	   tw.addAll(arr2);	   	   for(Iterator it = tw.iterator(); it.hasNext(); )	      System.out.println(it.next());	   	   TreeSet<Student> ts= new TreeSet<Student>(new ComparatorPerson());// E 是 Student， 传递的是其父类Person的比较器	   ts.addAll(arr1);	   	   for(Object o : ts.toArray())	      System.out.println(o);	   //上述的Worker 和 Student在TreeSet中排序时使用的比较器都是Person类实现的比较器   }}