Collections vs Streams

In this post, we will learn the difference between Collections and Streams in Java. This is a frequently asked question in Java interviews for beginners. Let's dive into it.

Difference between Collections and Streams in Java

Features Collections Streams
Main Use Collections are primarily used for storing and grouping data Streams are primarily used for performing operations on data
Manipulation Elements can be added or removed from collections Elements can't be added or removed from streams
Iteration Collections need to be externally iterated Streams are internally iterated
Traversal Collections can be traversed multiple times Streams can be traversed only once
Construction Collections are eagerly constructed Streams are lazily constructed
Examples List, Set, Map, etc Filtering, mapping, matching, etc

Related Collections Interview QA

  1. map() vs flatMap() in Java
  2. Collections vs Streams
  3. ArrayList vs Vector
  4. Iterator vs ListIterator
  5. HashMap vs HashTable
  6. HashSet vs HashMap
  7. Array vs ArrayList
  8. Fail-Fast Iterators vs Fail-Safe Iterators
  9. HashMap vs ConcurrentHashMap
  10. LinkedList vs ArrayDeque
  11. LinkedList vs Array
  12. LinkedList vs Doubly LinkedList
  13. Enum vs EnumSet in Java
  14. HashMap vs. TreeMap in Java
  15. Synchronized Collections vs. Concurrent Collections