Merge sort help

[enigma08]

I need to merge sort two linked lists, each has a header and the elements are all ints.

I've tried adapting some generic code, but have run into a problem - errors that are similar to this one:

split(AlgSet.LLAlgSet) in AlgSet.LLAlgSet cannot be applied to (Node<java.lang.Integer>)

I see how that is happening as I'm giving it an element next instead of an actual list. Can someone help me out? I don't think it'll take much to fix it, and I am not that skilled in Java.

public LLAlgSet merge (LLAlgSet list1, LLAlgSet list2) {
 
    if (list1 == null) return list2;
    if (list2 == null) return list1;
    if (list1.element < list2.element) {             
        list1.next = merge (list1.next, list2);
        return list1;
    } // end if
    else {
        list2.next = merge (list1, list2.next);
        return list2;
    } // end else*/
 
}
 
    public LLAlgSet merge_sort (LLAlgSet list1) { 
    if (list1 == null || list1.next == null)
           return list1; // checks for empty or single list
    LLAlgSet list2 = split (list1);
    list1 = merge_sort (list1);
    list2 = merge_sort (list2);
    return merge (list1, list2);
        }
 
    public LLAlgSet split (LLAlgSet list1) {
    if (list1 == null || list1.next == null) return null;
    LLAlgSet list2 = list1.next;
    list1.next = list2.next;
    list2.next = split (list2.next);
    return list2;
}