public Account(){}
public Account(double balance,String password){
this.id=new Random().nextLong();
this.balance=balance;
this.password=password;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
20. *（List）写一个函数reverseList，该函数能够接受一个List，然后把该List 倒序排列。 例如：
List list = new ArrayList(); list.add(“Hello”); list.add(“World”);
list.add(“Learn”); //此时list 为Hello World Learn reverseList(list);
//调用reverseList 方法之后，list 为Learn World Hello 21. **（Map，Hash 算法）有如下代码： import java.util.*; class MyKey{ int keyValue;
public MyKey(){}
public MyKey(int value){this.keyValue = value;} }
class MyValue{ String value;
public MyValue(){}
public MyValue(String value){this.value = value;} public String toString(){return value;} }
public class TestMap{
public static void main(String args[]){ Map map = new HashMap(); MyKey key1 = new MyKey(10); map.put(key1, new MyValue(“abc”));
map.put(new MyKey(10), new MyValue(“cde”)); System.out.println(map.get(key1)); System.out.println(map.size()); } }
写出该代码的输出结果。abc 2
22. **（Id，hashCode，equals）为Worker 类增加id 属性，用来唯一标识一