It appears that if a programmer supplied constructor, with a call to super ( ) is used, no other constructor can be invoked in that class ( ie it can't be overloaded). Is this normal behavior that is inherent to Java? Why?
abstract class Four {
Four ( ) { }
Four (int x) { }
}
class Three extends Four {
public Three ( String name) { }
Three (int t, int y) { }
}
class Two extends Three {
Two ( ) { super ( "number"); }
// Two (int t, int y) { } //causes an error when uncommented
}
class One extends Two {
public static void main (String [ ] args) {
new One ( );
}
}
no other constructor can be invoked in that class ( ie it can't be overloaded).
That's not true at all. The problem with your Two(int t, int y)
constructor is that it doesn't chain to any constructor explicitly, meaning that there's an implicit super()
call - which fails as there are no parameterless constructors in Three
1 . You can fix that in two ways:
Chain directly to a super constructor
Two (int t, int y) { super("number"); }
Chain to a constructor in the same class
Two (int t, int y) { this(); }
1 It doesn't have to be parameterless, strictly - if you add a Three(String... values)
constructor, that's okay. You need to have a constructor that can be invoked with an empty argument list.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.