LinkedList-Bubble Sort (Iterative) LinkedList

Given a singly linked list of integers, sort it using 'Bubble Sort.'
Note :
No need to print the list, it has already been taken care. Only return the new head to the list.
Input format :
The first and the only line of each test case or query contains the elements of the singly linked list separated by a single space.
Remember/Consider :
While specifying the list elements for input, -1 indicates the end of the singly linked list and hence, would never be a list element
Output format :
For each test case/query, print the elements of the sorted singly linked list.

Output for every test case will be printed in a seperate line.
Constraints :
0 <= M <= 10^3
Where M is the size of the singly linked list.

Time Limit: 1sec
Sample Input 1 :
10 9 8 7 6 5 4 3 -1
Sample Output 1 :
 3 4 5 6 7 8 9 10 
 Sample Input 2 :
10 -5 9 90 5 67 1 89 -1
Sample Output 2 :
-5 1 5 9 10 67 89 90 

*******************************************Code*******************************************
public static LinkedListNode<Integer> bubbleSort(LinkedListNode<Integer> head) {
		
		if(head==null || head.next==null)
			return head;
		for(int i=0;i<lengthLL(head)-1;i++)
		{
			LinkedListNode<Integer> prev=null;
			LinkedListNode<Integer> cur=head;
			LinkedListNode<Integer>next=cur.next;
			while(cur.next!=null)
			{
				if(cur.data>cur.next.data)
				{
					if(prev==null)
					{
						cur.next=next.next;
						next.next=cur;
						prev=next;
						head=prev;
					}
					else
					{
						next=cur.next;
						cur.next=next.next;
						prev.next=next;
						next.next=cur;
						prev=next;
					}
				}
				else{
					prev=cur;
					cur=cur.next;
				}
			}
		}
		return head;
	}
	private static int lengthLL(LinkedListNode<Integer> head)
	{
		int cnt=1;
		while(head.next!=null)
		{
			head=head.next;
			cnt++;
		}
		return cnt;
	}