Merge two Sorted Linked lists

Given two sorted Linked Lists, we need to merge them into the third list in sorted order. Complexity – O(n)

public static Node mergeList(Node a, Node b) {
  Node result = null;
  if (a == null)
   return b;
  if (b == null)
   return a;

  if (a.value <= b.value) {
   result = a;
   result.next = mergeList(a.next, b);
  } else {
   result = b;
   result.next = mergeList(b.next, a);
  }
  return result;
 }