Difference Between List VS Set In Java

List VS Set In Java: In this article, we will discuss the difference between List and Set in detail i.e.; List v/s Set

Both interfaces directly extend Collection interface, but they are a few differences between them Lets us move on and discuss key differences between them

List vs Set In Java

List
Set
It stores elements according to insertion order, insertion order is preservedSet stores elements in random order, as it uses hashing techniqueInsertion order isn’t preserved
While iterating List items, elements will be retrieved as per insertion orderWhile iterating Set items, elements will be retrieved in random order
It allows duplicate elementsSet doesn’t allow duplicate elements i.e.; it stores only unique elementsNote: if the same element is added again, there won’t be any compile-time or runtime error, just that add() method returns false;
Any number of the NULL object is allowed to add to the ListMaximum of one NULL is allowed

When to use List?

  • If the business requirement is to preserve insertion order and
  • adding duplicate elements is not a big concern
  • then List is the good choice to store the group of elements
  • Example: it could be ArrayList or LinkedList or Vector, etc

When to use Set?

  • If the business requirement is to avoid storing duplicate elements
  • And storing only unique elements
  • Where insertion order isn’t a big factor while iterating items
  • then Set is the good choice to store the group of elements
  • Example: it could be HashSet, etc

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