GO Interfaces and Polymorphism

Question 1

How does Go determine if a type implements an interface?

Accepted Answer

The type must have all methods in the interface with matching signatures

Answer

The type must declare it with `implements`

Answer

The type must embed the interface

Answer

The type must be registered with the compiler

Question 2

What is the empty interface `interface{}` (or `any`) equivalent to?

Accepted Answer

A type that holds any value since all types satisfy it

Answer

A nil pointer

Answer

A map of type metadata

Answer

An interface with one method

Question 3

What is a type assertion in Go?

Accepted Answer

Extracting the concrete value and type from an interface at runtime

Answer

Declaring a variable as a specific type at compile time

Answer

Casting between numeric types

Answer

Checking interface satisfaction at compile time

Question 4

What does a type switch allow you to do in Go?

Accepted Answer

Select a code branch based on the dynamic type of an interface value

Answer

Convert between numeric types

Answer

Match strings with regex

Answer

Switch between package versions

Question 5

Can a Go interface be embedded in another interface?

Accepted Answer

Yes, to compose larger interfaces from smaller ones

Answer

No, only structs can be embedded

Answer

Yes, but only one level deep

Answer

No, Go does not support interface composition

Question 6

What is the `Stringer` interface in Go?

Accepted Answer

An interface from `fmt` requiring `String() string`, used for custom string formatting

Answer

An interface requiring a `Print() string` method

Answer

A built-in type for string manipulation

Answer

A method to compare strings