Please, what is wrong in code below? Why do I get compiler error "cannot
find symbol variable date" in compareTo method of class TestItem?

Thank you!

public class Test<TestItem> implements Iterable<TestItem> {

   public class TestItem implements Comparable<TestItem> {

       public Date date;

       public TestItem() {
       }

       public int compareTo(TestItem anotherItem) {
           return date.compareTo(anotherItem.date);
                                                                     ^
*** Cannot find symbol: variable date ***___|

       }
   }

   private Vector<TestItem> items;

   public Test() {
       items =  new Vector<TestItem>();
   }

   public Iterator<TestItem> iterator() {
       return items.iterator();
   }

}