Java generics issue: Class “not within bounds of type-variable” error.

Question

I\'m working on a project for class that involves generics.

public interface Keyable  {public String getKey();}

public interface DataElement extend         


        

Answer 1

In MySearchTree the K of the base type is Course. So K must "extend" Comparable> & Keyable. But it doesn't, it extends Comparable> & Keyable.

I guess DataElement should be generified in a similar manner to Comparable or Enum.

public interface Keyable  {public String getKey();}

public interface DataElement> extends Comparable>, Keyable, Serializable {...}
public class Course implements DataElement {...}


public interface SearchTree> & Keyable> extends Serializable {...}
public class MySearchTree implements SearchTree {