package packB;class Student { //定義學生類 public String st = "student";}class Worker { //定義工人類 public String wo = "worker";}//定義泛型類class Operate<type> { // <type> 是給不確定的類型自定義的名字 private type elem; public void setElem( type t ) { //設置元素值方法 elem = t; } public type getElem() { //返回元素值方法 return elem; }}public class GenericDemo { public static void main(String[] args) { Operate<Student> obj = new Operate<Student>(); //表明操作的類型是Student類  obj.setElem( new Student() ); Student stu = obj.getElem(); //上面的代碼已經使用泛型說明了操作的對象，這里不需要強轉  sop(stu.st); } public static void sop(Object obj) { System.out.println(obj); System.out.println(); }}