No it is not. However, it is totally irrelevant for 99% of jobs require programming skills. Being 15 years in this business I haven't seen linked lists being used for any particular problem, but I understand that when you work in the right industry it is invaluable. If I had to implement it I would probably use a library and I would educate myself on the subject. I usually find programmers running into many other issues that don't show up during interviews.

Few questions I usually ask:

- How can you make sure that your Java application runs on the server not only on your laptop? (I take any answers: containers, single JAR, etc.)

- What is printed out

def add_list(val, list=[]):

    list.append(val)

    return list

print add_list(10)

print add_list(20)

print add_list(123,[])

- Explain recursion

Funny to see how a non-trivial amount of programmers fail to answer these questions.