Scala Interview Questions and Answers

There are four types of identifiers:

• Alphanumeric Identifiers: Contain letters, digits, and underscores. Example - myVal.
• Operator Identifiers: Contain operator characters. Example - +
• Mixed Identifiers: Contains underscore and an operator identifier. Example - myVar
• Literal Identifiers: Contain arbitrary string in backticks(`). Example `class.`

A lambda in Scala is an expression that does not reference value or a variable. Instead, it references an anonymous function. Scala supports lambda expressions in different forms. Developers use lambda expressions because of the convenience, decoupling, and reusability that it provides.

Functions in Scala are first-class values. This means that a function can be passed as a parameter or returned as a result. The Higher-order functions in Scala take other purposes as parameters and return a role as a result. This functionality provides flexibility in composing programs.

In Scala, Closure is a function in which the return value of a service is based on the amount of variables, which have been declared outside that function.

Currying is a way to transform a role with multiple arguments into a series of different tasks with a single discussion each. This feature helps the developers when they are working with higher-order functions.

A data type in Scala instructs the compiler about kind of value that needs to be stored in a specific location. In Scala, there are no primitive data types because everything in Scala is treated as an object.

Here are the data types:

• Byte
• Short
• Int
• Long
• Float
• Double
• Char
• String
• Boolean
• AnyRef
• Nothing
• Null
• Unit
• Any

Operators in Scala are symbols that operate on values. These values are called operands. Operators are essential elements of any programming language, as they allow the developers to perform various types of activities on operands.

This is one of the frequently asked Scala interview questions.

Scala has the following operators:

• Arithmetic Operators
• Relational Operators
• Logical Operators
• Assignment Operators
• Bitwise Operators

The foldLeft method in Scala is a member of the TraversableOnce trait. Using this method is essential in a recursive function and helps the developers prevent stack-overflow exceptions. This method also allows the developers to specify an initial value.

The problem of Multiple inheritances in Scala is referred to as the diamond problem. This problem occurs when a Class extends more than one Traits of the same method definition. The inability to decide on the best implementation method to choose leads to Diamond Problem. In Scala, the diamond problem gets resolved through the mechanism of Traits and the class linearization rules.

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. Scala provides lightweight syntax that helps developers define anonymous functions. Scala allows 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.

The unique feature that makes Scala standout from the rest is its ability to scale and expand. It has almost eliminated the common problems associated with other popular languages.

Why it is used?

Scala can be used in many ways, including in android apps, desktop apps, data processing, front-end and back-ends of web applications, Hadoop programs, big data, and data analysis, data streaming, etc.