Top 50 scala Question and Answer 2025

Updated:01/01/2025 by Computer Hope

1. What is the difference between flatMap() and map() operations?
2. Write a lambda function in Scala, using map operation, which takes a sequence of salaries as input and outputs double of every element from input.
3. How will you determine whether a function causes a shuffle or not without the help of documentation?
4. What is the difference between Singleton and Companion objects?
5. What happens when we create an instance of a class without the ‘new’ keyword?
6. What are the types of program evaluation in Scala?
7. What do you mean by Literals? What are the different types of Scala literals?
8. What is the difference between var, val and def in Scala?
9. Can a companion object in Scala access the private members of its companion class in Scala?
10. Differentiate Scala’s == And Java’s == Operator?
11. What is pattern matching?
12. What is for-comprehension in Scala?
13. What is Seq in Scala collection?
14. What is a ‘Scala set’? How will you declare immutable set?
15. How does yield work in Scala?
16. What is an anonymous object in Scala?
17. What is ‘Option’ and why it is used in Scala?
18. How apply and unapply methods used in Scala?
19. What Is The difference between call-by-value and call-by-name function parameters?
20. What is the use of Scala's App?
21. What is the Diamond Problem and how Scala solves it?
22. What is Monad in Scala?
23. What is Currying in Scala? What are its advantages?
24. How many types of constructors are used in Scala?
25. When using Scala stream, what are the considerations you must undertake?
26. What Is The Main Reason behind not having “static” keyword like Java in Scala?
27. What is a higher order function in Scala? Give example.
28. What is Scala Trait?
29. What is the difference between Seq and List in Scala?
30. What is a tail-recursive function in Scala?