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