Java：使用泛型扩展类

Question

How would I extend this class

 public class BST<E extends Comparable<E>> implements Iterable<E>

I am trying to create AVL tree class which extends BST.

I have

 public class AVL extends BST<E> 

but i'm getting error cannot find symbol for the E. I have tried

public class AVL<E extends BST<E>>

and receive error as well E1 extends BST but E2 extends Comparable.

Answer 1

Have it like this:

 public class AVL<E extends Comparable<E>> extends BST<E> 

Why?

You need to satisfy generic constraint of parameter E of BST class - <E extends Comparable<E>> and as you can see in the definition above, you are meeting that requirement.