Generics

[Suguna Gollapally]

import java.util.*;
class shape { }
class Rect extends shape { }
class cir extends shape { }
class shade extends Rect{}
class Test {

public static void add(List<? extends shape>l,int pos,Rect r) {

l.add(pos,r);
}

public static void main(String ar[]) {

List<shade>=new ArrayList<shade>();
add(l,o,newshade());
}
}
What is the error in this program?? is this add() method..

[Keith Lynn]

Originally posted by Suguna Gollapally:
import java.util.*;
class shape { }
class Rect extends shape { }
class cir extends shape { }
class shade extends Rect{}
class Test {

public static void add(List<? extends shape>l,int pos,Rect r) {

l.add(pos,r);
}

public static void main(String ar[]) {

List<shade>=new ArrayList<shade>();
add(l,o,newshade());
}
}
What is the error in this program?? is this add() method..

Because the parameter to the method accepts a List containing shape or anything that extends shape, there is no way to allow anything to be added to the List in the method.