一个关于继承的问题

[bluerain1]

import java.sql.Date;

public class test{
public static void main(String[] args){
Date nowdate=new Date();
System.out.println("the year is"+nowdate.getYear());
}
}
为什么不能使用java.sql.Date的父类java.util.Date中的构造函数Date()呢？

[Jacky1206]

因为你没有引入java.util.Date
你只引入了java.sql.Date，那么当然它用这个Date方法了
据我所知，java默认引入的包好象是java.lang.*，不知道有没记错，谢谢。

[bluesmile979]

java.lang.Object
|
+--java.util.Date
|
+--java.sql.Date

所以import java.lang.*；就可以了。

[UserJavaPerson]

应该引入util
即：import java.util.*;

[hayai]

Class B extends Class A.
Class C extends Class B.
Then, if in Class B, there exists any Constructor, The Constructors in Class A is no longer available to Class C.
A lot of people never notice that, but that's exactly your problem. However, if you don't have any particular reason, it's not recommended to use java.sql.Date.
Use java.util.Date or java.util.Calendar.