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.
|
+--java.util.Date
|
+--java.sql.Date所以import java.lang.*;就可以了。
即:import java.util.*;
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.