In this solution I swapped the values instead of the references which is simpler , It may not be the correct approach to get familiar with LinkedList

Solution {

	public ListNode swapPairs(ListNode head) {
		// TODO: Write your code hereu
		ListNode current = head;
		while(current != null && current.next != null) {
			int t = current.val;
			current.val = current.next.val;
			current.next.val = t;
			current = current.next.next;
		}
		return head;
	}
}