Scala Interview Questions and Answers

Last updated on Mar 17, 2022
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Scala Interview Questions

Scalable Language, or Scala, is a general-purpose, hybrid functional programming language. Integrating the features of other technical and object-oriented languages, Scala is designed to run on JVM (Java Virtual Machine). This means Scala will enable you to use all the classes of Java SDK, including custom classes, of your Java open source projects. This information is often asked in Scala interview questions. Being used in most of the enterprise-level web apps, Scala provides lightweight syntax that helps developers define anonymous functions. The language supports high-level functions and allows nesting of those functions. Scala will enable developers to write general programming patterns efficiently by reducing the number of lines. This language also empowers the developers to write immutable codes, thus making it easy to apply parallelism and concurrency.

If you are preparing for the Scala language job interview, we have one of the biggest collection of Scala Interview Questions and Answers.

Most Frequently Asked Scala Interview Questions

Here in this article, we will be listing frequently asked Scala Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q11. What are the features of Scala?
These are key features:
  • Type inference
  • Singleton object
  • Immutability
  • Lazy computation
  • Case classes and Pattern matching
  • Concurrency control
  • String interpolation
  • Higher order function
  • Traits
  • Rich collection set
Q12. What do you mean by Scala map?

Scala Map is a collection of elements in pairs of key and values, where values can be retrieved using keys. Values are not unique, but the keys are unique. Scala supports two types of maps - mutable and immutable. By default, the language supports the immutable map. You can create a Scala map in two ways – by using comma separated pairs or by rocket operator.

Q13. What do you mean by “Type Inference” in Scala?

Type Interface is one of the unique features in Scala that help reduce the amount of coding for developers. Type Interface may be defined as the process used by the compiler to determine the type of value, variable, or return value of a function - based on the statement in which they are found.

Q14. Explain the difference between val and var in Scala?
Answer Val Var
1. Refers to value Refers to variable
2. Is constant Is changeable
3. Immutable declaration of variables Mutable declaration of a variable
4. Cannot reassign values once created Reassign values once its created
Q15. What is the difference between Function and Method in Scala?
Answer functions methods
1. Defined in Package Defined in a class
2. Can be accessed without objects Cannot be used without an object
Q16. Is Scala an OOP?

It is a programming language and it is also an object-oriented programming language like PHP, Java, Python, Ruby, Smalltalk, and others.

Q17. What is BitSet in Scala?

A bitset is a collection of non-negative integers that are depicted as arrays in Scala. Variable in size, these arrays are packed into 64-bit words. In a bitset, the most significant number determines the memory footprint.

Q18. What do you mean by ofDim in Scala?

It is a method in Scala that allows the developers to create multi-dimensional arrays. We can prepare you for Scala Interview Questions and Answers by informing you of the latest developments.

Q19. What are streams in Scala?

Streams are the type of lazy collections, or lazy lists, that get created when starting an element and then generate recursively using the same parts. This feature enhances program performance. Streams are similar to Lists, except that in Streams, the items get added only after being accessed.

Q20. What is a monad in scala? Explain

A Monad can be described as an object that wraps another object. In Scala, a class object is covered with a monad. Monads wrap objects and offer two operations - Identity through units, and bind through flatMap.

A Monad determines the best way to apply the program to underlying objects. A lot of recent Scala interview questions were based on this information.

Key Features of Scala Language
  • Singleton object
  • Concurrency control
  • Traits
  • Case classes and Pattern matching
  • String interpolation
  • Lazy computation

Classes and inheritance - two features that stand out in object-oriented programming (OOP) language - are supported in Scala. This enables the development and maintenance of modular software. Some other key features include objects, traits, and case classes.

The unique feature that makes Scala standout from the rest is its ability to scale and expand. Considered as one of the “future-proof” languages, it has almost eliminated the common problems associated with other popular languages. Regardless of the nature of the project you are handling, trust Scala to handle it.

Designed to compensate for the faults of Java, JVM views Scala and Java as same languages.

Development History of Scala Language

Martin Odersky started the design process of Scala at the EPFL in Switzerland in 2001. Odersky followed the work dome on Funnel, a programming language that combined ideas from Petri nets and functional programming. After an internal delay, the first version of Scala was publicly released in 2004 on the Java platform.

Latest Version

Latest version is 2.12.8, which was released in Dec 2018. With its first 2.12 release, Scala license got changed to Apache v2.0.

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