title: When to use HashMap over LinkedList or ArrayList and vice-versa
body: <p>What is the reason why we cannot always use a HashMap, even though it is much more efficient than ArrayList or LinkedList in add,remove operations, also irrespective of the number of the elements.</p>
  
  <p>I googled it and found some reasons, but there was always a workaround for using HashMap, with advantages still alive.</p>