Question

I am trying to create a BinarySearchTree using generics, but I am bumping into an error. I want my class to extend Number and Implement Comparable. So I declare it this way:

public class BinaryTree<K extends Number implements Comparable<? super K>, E>

But I am getting an error.

File: F:\Java\intro-prog-java\bookClasses\Lab_5\BinaryTree.java [line: 1]
Error: > expected

I cannot get whats wrong with it.

Answer 1

That’s the wrong syntax. Try this:

public class BinaryTree<K extends Number & Comparable<? super K>, E>

This syntax is described in the Bounded Type Parameters topic of the Java tutorials on generics as well as §4.4 of the Java Language Specification.