Need help... can't find the problem...

Question

I'm trying to copmli my program.. but I'm getting
some errors...
C:\Umass\CS210\Hw2\SinglyLinkedList.java:301: unreachable statement
          return NOT_FOUND;
^
C:\Umass\CS210\Hw2\SinglyLinkedList.java:316: variable p might not have been initialized
     return p;
^
import java.util.*;
public class SinglyLinkedList implements List
   * creatino of the SllIterator
  private class SllIterator implements Iterator
       private Node current;
       private Node lastVisited = null;
       private int expectedModCount = modCount;
     public boolean hasNext()
          if(expectedModCount != modCount)
               throw new ConcurrentModificationException();
          return true;
     public Object next()
          if(!hasNext())
               throw new NoSuchElementException();
          Object nextItem = current.data;
          lastVisited = current;
          current = current.next;
          return nextItem;
     public void remove()
          if(expectedModCount != modCount)
               throw new ConcurrentModificationException();
          if(lastVisited == null)
               throw new IllegalStateException();
          SinglyLinkedList.this.remove(lastVisited);
          lastVisited = null;
          expectedModCount++;     
  // an inner class: This is our node class, a singly linked node!
  private class Node
    Object data;
    Node next;
    Node(Object o, Node n)
      data = o;
      next = n;
    Node(Object o)
      this(o, null);
    Node( )
      this(null,null);
  private Node head; // the "dummy" head reference
  private int size;  // the number of items on the list
  private int modCount = 0;
  public SinglyLinkedList()
    head = new Node(); // dummy header node!
  public void add(int index, Object o)
            Node p = getNode(index);
            Node newNode = new Node(o, p);
            newNode.next = newNode;
            size++;
            modCount++;
  public boolean add(Object element)
       if (element == null) return false;
       // Check for dummy head node
       if (head.data == null)
            head = new Node(element, null);
    else
    // Traverse the list until we find the end
         Node next = head;
         while (next.next != null)
         next = next.next;
    next.next = new Node(element, null);
    size++;     
    return true;
  public boolean addAll(Collection c)
    return true;
  public boolean addAll(int index, Collection c)
    return true;
  public void clear()
       head = new Node("Head", null);
       size = 0;
  // write a recursive implementation here
  public boolean contains(Object o)
    return findPos(o) != NOT_FOUND;
  public boolean containsAll(Collection c)
    return true;
  public boolean equals(Object o)
    return true;
  // write a recursive implementation here
  public Object get(int index)
    return null;
  // NOT implemented: we don't cover hash codes
  // and hashing in this course
  public int hashCode()
    throw new UnsupportedOperationException();
  public int indexOf(Object o)
    return -1;
  public boolean isEmpty()
     return (size() == 0);
  public Iterator iterator()
    return null;
  public int lastIndexOf(Object o)
    return -1;
  // Not implemented: The following two operations are not supported
  // since we are using a singly linked list, which does not allow
  // us to iterate through the elements back and forth easily
  // (going back is the problem)
  public ListIterator listIterator()
    throw new UnsupportedOperationException();
  public ListIterator listIterator(int index)
    throw new UnsupportedOperationException();
  // write a recursive implementation here
  public Object remove(int index)
    return null;
  public boolean remove(Object o)
    return true;
  public boolean removeAll(Collection c)
    return true;
  public boolean retainAll(Collection c)
    return true;
  // write a recursive implementation here
  public Object set(int index, Object element)
    return null;
  public int size()
    return size;
  // NOT implemented: to keep the homework reasonably simple
  public List subList(int fromIndex, int toIndex)
    throw new UnsupportedOperationException();
  public Object[] toArray()
    return null;
  public Object[] toArray(Object[] a)
    // you'll find this piece of code useful
    // it checks the exact type of the array passed as a parameter
    // in order to create a larger array of the same type.
    if (a.length < size)
      a = (Object[])java.lang.reflect.Array.
     newInstance(a.getClass().getComponentType(), size);
    // ... you need to write more code here!
    return a;
  private static final Node NOT_FOUND = null;
  //FindPos
  private Node findPos(Object o)
       for(Node p = head.next; ; p = p.next)
            if(o == null)
                 if(p.data == null)
                 return p;
            else if(o.equals(p.data))
            return p;
            return NOT_FOUND;
  //Get Node
  private Node getNode(int index)
       Node p;
       if(index < 0 || index > size())
            throw new IndexOutOfBoundsException();
       if(index < size() /2)
            p = head.next;
            for(int i = 0; i < index; i++)
              p = p.next;
       return p;
  //Print The node
  private static void print(Node n)
       Node current = n.next;
       while (current != null){
            System.out.println(current.data);
            current = current.next;
  public static void main (String[] args){
       System.out.println("Singly Linked List");
       System.out.println();
       SinglyLinkedList l = new SinglyLinkedList();
       l.add("F");
       l.add("K");
}       

Answer 1

C:\Umass\CS210\Hw2\SinglyLinkedList.java:301: unreachable statement
return NOT_FOUND;
^
C:\Umass\CS210\Hw2\SinglyLinkedList.java:316: variable p might not have been initialized
return p;
^
The first problem is because your "for" loop has no "while" condition in it:
for(Node p = head.next; ; p = p.next)...
Therefor, the only way out of the loop is via break, return, or exception. In your case, you don't "break" out of the loop, so there's no way it can get to this statement.
The second problem, you didn't cover all cases to set "p", so it won't let you return an un-initialized value.