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Question-1. What is a functional interface in Scala?
Answer-1: A functional interface is a trait with exactly one abstract method, used for lambdas.
Question-2. How do you define a lazy value in Scala?
Answer-2: Use the lazy keyword. Example: lazy val result = compute();.
Question-3. What is the difference between Stream and List?
Answer-3: Stream supports lazy evaluation, while List is eagerly evaluated.
Question-4. What is the significance of Predef in Scala?
Answer-4: Predef contains commonly used methods and implicit conversions, automatically imported into every Scala program.
Question-5. What are implicit parameters in Scala?
Answer-5: Implicit parameters are automatically filled by the compiler when marked with implicit.
Question-6. What is tail recursion in Scala?
Answer-6: Tail recursion is a recursion where the recursive call is the last operation, optimized by the compiler.
Question-7. What is @annotation.tailrec?
Answer-7: It is a Scala annotation that ensures a method is tail-recursive, producing a compiler error otherwise.
Question-8. What is the FlatMap function in Scala?
Answer-8: flatMap transforms a collection and flattens the result into a single collection.
Question-9. What is Scala's BigInt class?
Answer-9: BigInt is used for arbitrary-precision integers.
Question-10. What is Scala's BigDecimal class?
Answer-10: BigDecimal is used for arbitrary-precision floating-point numbers.
Question-11. What is Spark's relation to Scala?
Answer-11: Apache Spark is a distributed data processing framework written in Scala, and Scala is its primary language.
Question-12. What is the @Override annotation used for?
Answer-12: It ensures a method overrides a superclass method, throwing an error if it doesn't.
Question-13. How do you convert a list to a string in Scala?
Answer-13: Use the mkString method. Example: List(1, 2).mkString(", ").
Question-14. What is the significance of package object in Scala?
Answer-14: A package object allows defining shared methods, values, or type aliases for a package.
Question-15. What is Scala?
Answer-15: Scala is a high-level programming language that combines object-oriented and functional programming paradigms.
Question-16. Who developed Scala?
Answer-16: Scala was developed by Martin Odersky in 2004.
Question-17. What does Scala stand for?
Answer-17: Scala stands for "Scalable Language."
Question-18. Is Scala statically or dynamically typed?
Answer-18: Scala is statically typed.
Question-19. What is the latest stable version of Scala?
Answer-19: The latest version varies; always check the Scala website.
Question-20. What is an object in Scala?
Answer-20: An object is a singleton instance, defined using the object keyword.
Question-21. How is object different from class in Scala?
Answer-21: object defines a singleton, whereas class is a blueprint for creating multiple instances.
Question-22. What are case classes in Scala?
Answer-22: Case classes are immutable and used for pattern matching. Defined using case class.
Question-23. How do you define a function in Scala?
Answer-23: Use the def keyword. Example: def add(a: Int, b: Int): Int = a + b.
Question-24. What is the significance of val and var in Scala?
Answer-24: val is immutable (like final in Java), while var is mutable.
Question-25. What is the use of the apply method in Scala?
Answer-25: apply allows objects to be called as if they were functions.
Question-26. What is a trait in Scala?
Answer-26: A trait is like an interface in Java but can have both abstract and concrete methods.
Question-27. How do you inherit a trait in Scala?
Answer-27: Use the extends and with keywords. Example: class MyClass extends MyTrait.
Question-28. What is an implicit in Scala?
Answer-28: Implicits provide default values or automatic conversions in a scope.
Question-29. What is the difference between map and flatMap?
Answer-29: map applies a function and wraps the result in a container, while flatMap flattens nested structures.
Question-30. What is a companion object in Scala?
Answer-30: A companion object is an object with the same name as a class, sharing access to its private members.
Question-31. What is the Option type in Scala?
Answer-31: Option represents optional values, which can be Some(value) or None.
Question-32. What is pattern matching in Scala?
Answer-32: Pattern matching is a mechanism for checking a value against a pattern using the match keyword.
Question-33. How do you create a list in Scala?
Answer-33: Use List. Example: val myList = List(1, 2, 3).
Question-34. What is the difference between List and Array in Scala?
Answer-34: List is immutable, whereas Array is mutable and fixed in size.
Question-35. What is a higher-order function in Scala?
Answer-35: A higher-order function is a function that takes other functions as parameters or returns a function.
Question-36. What is a closure in Scala?
Answer-36: A closure is a function that captures free variables from its surrounding scope.
Question-37. What is lazy evaluation in Scala?
Answer-37: Lazy evaluation delays computation until the result is required, using the lazy keyword.
Question-38. What is the yield keyword in Scala?
Answer-38: yield is used in for-comprehensions to construct and return a collection.
Question-39. What is a tuple in Scala?
Answer-39: A tuple is a collection of fixed-size elements of different types. Example: (1, "Scala").
Question-40. What is the purpose of the sealed keyword?
Answer-40: sealed restricts subclassing to within the same file.
Question-41. What are futures in Scala?
Answer-41: Futures allow asynchronous computation and handle results or errors once available.
Question-42. What is the Either type in Scala?
Answer-42: Either represents two possibilities: Left for failure and Right for success.
Question-43. How do you handle exceptions in Scala?
Answer-43: Use try, catch, and finally blocks, or use Try for functional exception handling.
Question-44. What is the difference between Nil and null in Scala?
Answer-44: Nil is an empty list, while null represents a null reference.
Question-45. How does Scala's for-comprehension work?
Answer-45: For-comprehensions allow iteration and transformation of collections in a concise syntax.
Question-46. What is a Monad in Scala?
Answer-46: A Monad is a design pattern used for chaining operations while handling context like Option or Future.
Question-47. What is Type Inference in Scala?
Answer-47: Scala's compiler can automatically determine variable and return types, reducing explicit type annotations.
Question-48. What is the difference between == and eq in Scala?
Answer-48: == checks value equality, while eq checks reference equality.
Question-49. What is an abstract class in Scala?
Answer-49: An abstract class can have both abstract and non-abstract members and is extended by other classes.
Question-50. How do you define a singleton object in Scala?
Answer-50: Use the object keyword. Example: object Singleton { def method = "Single" }.
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