Doubly linked list insertion at given position

//Doubly linked list insertion at given position

import java.util.*;

class Node {
	int data;
	Node next;
	Node prev;
	Node(int data) {
	    this.data = data;
	    next = prev = null;
	}
}

class DLinkedList {
	Node newNode(Node head, int data) {
		Node n = new Node(data);
		if(head == null) {
		    head = n;
		    return head;
		}

		head.next = n;
		n.prev = head;
		head = n;
		return head;
	}
	
	
	void printList(Node node) {
		Node temp = node;
		while(temp.next != null) {
			temp = temp.next;
		}
		
		while(temp.prev != null) {
			temp = temp.prev;
		}
		
		while(temp != null) {
			System.out.print(temp.data+" ");
			temp = temp.next;
		}
		System.out.println();
	}
	
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		DLinkedList DLL = new DLinkedList();
		int t = sc.nextInt();
		
		while(t > 0) {
			Node temp;
			Node head = null;
			Node root = null;
			int n = sc.nextInt();

			for(int i = 0; i < n; i++) {
				int x = sc.nextInt();
				head = DLL.newNode(head,x);
			    if(root == null)    root = head;
			}

			head = root;
			int pos = sc.nextInt();
			int data = sc.nextInt();
	    GfG g = new GfG();
	    g.addNode(head,pos,data);
			DLL.printList(head);

			while(head.next != null) {
				temp = head;
				head = head.next;
			}
		    t--;
		}
	}
}

class Node {
	int data;
	Node next;
	Node prev;

	Node(int data) {
	    this.data = data;
	    next = prev = null;
	}
}

class GfG {
    void addNode(Node head_ref, int pos, int data) {
  		Node newNode = new Node(data);
      Node curr = head_ref;
	    int count = 0;
		    
	    while(curr != null) {
	        if(count == pos) {
	            break;
            }
		        
	        count++;
	        curr = curr.next;
	    }
		    
	    if(curr.next == null) {
	        curr.next = newNode;
	        newNode.prev = curr;
	        newNode.next = null;
	    }
		    
	    else {
		    Node front = curr.next;
    	    front.prev = newNode;
	        newNode.next = front;
            newNode.prev = curr;
            curr.next = newNode;
	    }
	}
}