Traverse Binary Tree In Post Order - POIterator Not Working Properly

I have a Java Code:

POIterator mh_sh_highlight_all('java');

class that implements an Iterator.

A new instance of the Java Code:

POIterator mh_sh_highlight_all('java');

Class is supposed to traverse a binary tree in Post Order. But when I attempt to test a

Java Code: POIterator mh_sh_highlight_all('java');

Object in my main class, it doesn't work as its supposed to. I might be implementing it wrong.

Java Code:

public PostOrderIterator<E> implements Iterator<E>{
Deque<BNode<E>> somestack = new LinkedList<BNode<E>>();
BNode<E> position;
public POIterator(BNode<E>root){
somestack = new LinkedList<BNode<E>>();
somestack.push(root);}

[Code] ....