clone问题!
一个员工类Employee
class Test
{
public static void main(String[] args)
{
Employee worker=new Employee("tom",50000);
worker.setHireday(2000,1,1);
Employee copy=(Employee)work.clone();
...
}
}
class Employee implements cloneable
{
public Employee(String n,double s)
{
...
}
public Object clone()
{
try
{
Employee cloned=(Employee)super.clone();
cloned.hireDay=(Date)hireDay.clone();
return cloned;
}
catch(cloneNotSupportedException)
{
return null;
}
}
...
private Date hireDay;
}
我的问题是:1。cloned.hireDay=(Date)hireDay.clone()里的hireDay.clone()是怎样工作的?有什么作用?
2。String是不可变的类,Date是可变的 是指的什么?能不能举个例子。