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Question: Can you explain the concept of type classes in Scala?
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Answer: The type classes are a design pattern in Scala for ad-hoc polymorphism, which allows defining
behavior independently of a type's hierarchy. Type classes are typically implemented as traits with generic methods,
and instances of type classes are provided for specific types.
Type classes enable writing generic code that operates on a wide range of types while still providing
type safety and compile-time checks.
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Question: Can you explain the concept of 'type erasure' in Scala?
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Answer: The 'type erasure' is a process performed by the Scala compiler during compilation to remove type
parameters and type arguments from generic types. This is done to ensure compatibility with Java's runtime representation
of generics, which does not include type information.
Type erasure can sometimes lead to challenges in pattern matching and runtime reflection.
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Question: Can you explain the concept of variance in Scala?
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Answer: The variance in Scala defines how subtyping relationships between parameterized types relate to subtyping
relationships between their type parameters. Scala supports three variance annotations:
+ (covariant), - (contravariant), and no annotation (invariant).
Variance annotations ensure type safety and allow for more flexible usage of parameterized types in generic code.
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Question: What is the difference between List, Seq, and Vector in Scala?
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Answer: Below please find the differences:
• List is an immutable sequential collection that represents a linked list.
• Seq is a trait representing a sequence of elements with a defined order.
• Vector is an immutable indexed sequence that provides efficient random access and updates.
While List and Seq preserve insertion order, Vector provides fast indexed access and updates.
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Question: What is implicit resolution in Scala?
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Answer: The implicit resolution is the process by which the Scala compiler searches for implicit values, parameters,
conversions, or classes that satisfy specific requirements.
Implicit resolution is used extensively in Scala for providing default values, injecting dependencies, and
enabling implicit conversions.
Implicit resolution follows a set of rules defined by the Scala language specification.
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Question: Can you explain the difference between Future and Promise in Scala?
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Answer: The Future represents a read-only placeholder for a value that may or may not be available
in the future, typically resulting from asynchronous computations.
Promise is a writable, single-assignment container for a value that allows completing a Future with a value
or an exception.
Promise is used to produce values for Future instances, while Future is used to consume them.
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Question: Can you explain the concept of currying versus partial application in Scala?
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Answer: In Scala, currying is the process of converting a function with multiple arguments into a
sequence of functions, each taking a single argument.
Partial application, on the other hand, involves fixing a subset of a function's arguments to
create a new function with fewer parameters.
Currying is a special case of partial application where the new functions are created in a specific order.
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