SortedList implements Serializable

[Cosmicus]

I am using JDK 1.2 on IBM comp. machine for this project.<br>
<br>
The project is to create a sorted list from a bunch of instances of a class called Student. Student consists of Student_number, and student name. Another class called SortedList has a method "insert", which does the sorting.<br>
<br>
eg. of bunch<br>
//this is in the test.java class<br>
SortedList s = new SortedList();<br>
s.insert(7, new Student(7, "Jack"));<br>
s.insert(1, new Student(1, "Helen"));<br>
s.insert(9, new Student(9, "Moris"));<br>
s.insert(3, new Student(3, "Buddy"));<br>
<br>
//SortedList class has method "insert", which contains the<br>
//following arguments:<br>
public void insert(long key, Object stu)<br>
<br>
//the interface Sortable is implemented in the Student class<br>
interface Sortable {<br>
boolean compare(Object current, Object next);<br>
}<br>
<br>
//Now, <br>
class Student implements Serializable, Sortable<br>
//and<br>
class SortedList extends SLList implements Serializable {<br>
//SLList = Singly-Linked List (non-circular)<br>
<br>
The question is why do I get this compilation message:<br>
"Interface Serializable of class SLList not found.", when SLList is<br>
also implemented with the interface Serializable?<br>