text: I have an interface and I'm trying to implement.
  package data_structures; public interface ListADT<E> extends Iterable<E> { //Method Signatures }
  and
  package data_structures; public class LinkedListDS<E> implements ListADT<E> { //Code }
  And when I try to compile the class I get
  --------------------
  LinkedListDS.java:3 error: cannot find symbol
  public class LinkedListDS<E> implements ListADT<E> {
  ____________________________________^
  symbol: class ListADT
  --------------------
  And I'm not really sure what I'm doing wrong here or what exactly Java wants me to do to correct this error.
  What are you using to compile? If the command line, and not an IDE which will do this for you, then compile the interface, first.