{"id":19734,"date":"2018-06-28T04:00:52","date_gmt":"2018-06-28T04:00:52","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=19734"},"modified":"2021-12-04T10:15:14","modified_gmt":"2021-12-04T04:45:14","slug":"scala-interview-questions","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/scala-interview-questions\/","title":{"rendered":"Top 30 Scala Interview Questions (Latest)"},"content":{"rendered":"

In this best 30 Scala Interview Questions, we are going to cover all the frequently asked questions in Scala Interview. These Scala Interview Questions are provided by Scala<\/strong><\/a> experts which are beneficial for both freshers as well as experienced. You can gain a better understanding of Scala with these Scala Interview Questions and answers. Follow each link, to gain in-depth knowledge of Scala.
\nSo let’s start Scala Interview Questions.<\/p>\n

Scala Interview Questions and Answers<\/h3>\n

Below, we are discussing some important Scala Interview Questions for both freshers and experienced:<\/p>\n

Q.1. What is ofDim in Scala?<\/strong><\/p>\n

ofDim() is a method in Scala that lets us create multidimensional arrays. Since these let us store data in more than one dimension, we can store data like in a matrix. Let\u2019s take an example.<\/span><\/p>\n

scala> import Array.ofDim\r\nimport Array.ofDim\r\nscala> var a=ofDim[Int](3,3)\r\na: Array[Array[Int]] = Array(Array(0, 0, 0), Array(0, 0, 0), Array(0, 0, 0))\r\nscala> var k=1\r\nk: Int = 1\r\nscala> for(i<-0 to 2){\r\n    | for(j<-0 to 2){\r\n    | a(i)(j)={i+k}\r\n    | k+=1\r\n    | }\r\n    | k-=1\r\n    | }\r\nscala> a<\/pre>\n
res12:<\/strong> Array[Array[Int]] = Array(Array(1, 2, 3), Array(4, 5, 6), Array(7, 8, 9)).<\/span><\/p>\n
Q.2. What do you have to say about exception propagation in Scala?<\/strong><\/p>\n
When a function experiences an exception, it looks for a handler to deal with it. When it fails to find one, it searches for one in the caller method. Failing there, it looks for yet another in the next caller in the chain. Whenever it does find a handler, it makes it catch the exception. This is exception propagation.<\/span><\/p>\n
Read Scala Functions<\/a><\/strong><\/p>\n
Q.3. What is a BitSet?<\/strong><\/p>\n
A bitset is a set of non-negative integers depicted as arrays. These arrays are variable in size and packed into 64-bit words. The largest number in a bitset determines its memory footprint. Let\u2019s take an example.<\/span><\/p>\n
scala> import scala.collection.immutable._\r\nimport scala.collection.immutable._\r\nscala> var nums=BitSet(7,2,4,3,1)\r\nnums: scala.collection.immutable.BitSet = BitSet(1, 2, 3, 4, 7)\r\nscala> nums+=9  \/\/Adding an element\r\nscala> nums<\/pre>\n
res14: scala.collection.immutable.BitSet = BitSet(1, 2, 3, 4, 7, 9)<\/span><\/p>\n
scala> nums-=4  \/\/Deleting an element\r\nscala> nums<\/pre>\n
res16: scala.collection.immutable.BitSet = BitSet(1, 2, 3, 7, 9)<\/span><\/p>\n
scala> nums-=0  \/\/Deleting an element that doesn\u2019t exist\r\nscala> nums<\/pre>\n
res18: scala.collection.immutable.BitSet = BitSet(1, 2, 3, 7, 9)<\/p>\n
Q.4. What is a vector in Scala?<\/strong><\/p>\n
A vector is a general-purpose data structure that is immutable. We can use it when we want to hold a huge number of elements and want random access to them. This data structure extends the trait IndexedSeq and the abstract class AbstractSeq.<\/span><\/p>\n
scala> import scala.collection.immutable._\r\nimport scala.collection.immutable._\r\nscala> var v1=Vector.empty\r\nv1: scala.collection.immutable.Vector[Nothing] = Vector()\r\nscala> var v2=Vector(7,2,4,3,1)\r\nv2: scala.collection.immutable.Vector[Int] = Vector(7, 2, 4, 3, 1)\r\nscala> var v3:Vector[Int]=Vector(8,2,6,5,9)\r\nv3: scala.collection.immutable.Vector[Int] = Vector(8, 2, 6, 5, 9)\r\nscala> v3=v3 :+7  \/\/Adding a new element\r\nv3: scala.collection.immutable.Vector[Int] = Vector(8, 2, 6, 5, 9, 7)\r\nscala> v2++v3  \/\/Merging two vectors<\/pre>\n
res19: scala.collection.immutable.Vector[Int] = Vector(7, 2, 4, 3, 1, 8, 2, 6, 5, 9, 7)<\/span><\/p>\n
scala> v3.reverse  \/\/Reversing a vector<\/pre>\n
res20: scala.collection.immutable.Vector[Int] = Vector(7, 9, 5, 6, 2, 8)<\/span><\/p>\n
scala> v3.sorted  \/\/Sorting a vector<\/pre>\n
res21: scala.collection.immutable.Vector[Int] = Vector(2, 5, 6, 7, 8, 9)<\/span><\/p>\n
In results 20 and 21, we do not assign the expression to any variable, so not that this doesn\u2019t change the original vectors.<\/span><\/p>\n
Q.5. Explain streams in Scala.<\/strong><\/p>\n
A stream is a lazy list as it evaluates elements only when it needs to. This lazy computation enhances program performance.<\/span><\/p>\n
scala> val stream=177#::199#::69#::Stream.empty\r\nstream: scala.collection.immutable.Stream[Int] = Stream(177, ?)<\/pre>\n
Since we don\u2019t need the second element yet, Scala doesn\u2019t evaluate it.<\/span><\/p>\n
scala> val stream1=(1 to 7).toStream\r\nstream1: scala.collection.immutable.Stream[Int] = Stream(1, ?)\r\nscala> stream.head<\/pre>\n
res22: Int = 177<\/span><\/p>\n
scala> stream.map{_*2}<\/pre>\n
res24: scala.collection.immutable.Stream[Int] = Stream(354, ?)<\/span><\/p>\n
Learn Scala Arrays and Multidimensional Arrays in Scala<\/a><\/strong><\/p>\n
Q.6. What are the advantages of Scala?<\/strong><\/p>\n
Among various other benefits of the language, here are a few:<\/span><\/p>\n