title: How to pass a Linked list as a function parameter in java
body: <p>I am struggling in "How to pass a Linked list as a function parameter" in java. 
  This method is supposed to take another linked list as a parameter, and add the contents of this linked list to the calling instance's linked list. Adding the elements should only be done if the element does not already exist. All elements to be added should be added at the end of the linked list.</p>