Hi can you help me answer the following Data Structure and Algorithm Question using Java with step by step detailed solution and explanation? Thank you very much!

4. Code for implementing a circular doubly-linked list is given below: public interface Iterator public boolean hasNext(); public boolean hasPrevious (); public int next () throws Exception; // move iterator to the next position, // then returns the value at that position. public int previous() throws Exception; // return the value at current position, // then move the iterator back one position. public void set(int value); public class DListIterator implements Iterator { DListNode currentNode; // interested position DListIterator(DListNode theNode) { currentNodetheNode; public boolean hasNext()t // always true for circular list return currentNode.nextNode != null; public boolean hasPrevious() f // always true for circular list return currentNode.previousNode !- null; public int next () throws Exception { // Throw exception if the next data // does not exist. if (!hasNext()) throw new NoSuchElementException(); currentNodecurrentNode.nextNode; return currentNode.data public int previous() throws Exception if (!hasPrevious ()) throw new NoSuchElementException(); int data-currentNode.data currentNode currentNode.previousNode; return data; public void set(int value) { currentNode.data = value; class DListNode { DListNode (int data) { this(data, nul1, null); DListNode (int theElement, DListNode n, DListNode p) data-theElement; nextNode = n; previousNodep; // Friendly data; accessible by other package routines int data DListNode nextNode, previousNode; public class CDLinkedList f DListNode header; int size; static final int HEADERVALUE = -9999999; public CDLinkedList() 1 size = 0; headernew DListNode(HEADERVALUE); makeEmpty);/ecessary, otherwise next/previous node will be null public boolean isEmpty) return header.nextNodeheader; public boolean isFull() { return false; public void makeEmpty() { header.nextNode = header; header.previouSNode header; // put in new data after the position of p. public void insert(int value, Iterator p) throws Exception { if (p == null II ! (p instanceof DLstterator)) throw new Exception() DListIterator p2(DListIterator) p; if (p2.currentNodenull) throw new Exception); Need to be filled! See question 4 a) // return position number of value found in the list. // otherwise, return -1 public int find(int value) throws Exception iterator itr new DLstiterator(header); int index - -1; while (itr.hasNext()) int v- itr.next) index++ DListiterator tr2 (DListiterator) itr; if (itr2.currentNode == header) return 1; if (vvalue) return index; // return the position of value. return-1; // return data stored at kth position public int findKth(int kthPosition) throws Exception if (kthPosition