Groovy and Grails Groovy Language Fundamentals & Metaprogramming 3

Question 1

Which Groovy AST transformation makes a class immutable by generating a constructor with all fields and making them final?

Accepted Answer

@Immutable

Answer

@Singleton

Answer

@Canonical

Answer

@CompileStatic

Question 2

What does `@CompileStatic` do in Groovy?

Accepted Answer

Disables dynamic dispatch and performs type checking at compile time like Java

Answer

Forces the class to extend a static inner class

Answer

Marks the class as a compile-time constant

Answer

Generates static factory methods for the annotated class

Question 3

In Groovy, what is a GString?

Accepted Answer

A string literal with embedded expressions evaluated at runtime using `${}`

Answer

A Google-specific extension of the String class

Answer

A compressed binary string format

Answer

A string that enforces character encoding validation

Question 4

What is the `inject` method in Groovy's GDK equivalent to in functional programming?

Accepted Answer

reduce/fold

Answer

map

Answer

filter

Answer

flatMap

Question 5

How does Groovy handle operator overloading?

Accepted Answer

By implementing named methods that correspond to each operator (e.g., `plus` for `+`)

Answer

Using the `operator` keyword before method definitions

Answer

Through annotations placed on the class declaration

Answer

By implementing the `Operator` interface

Question 6

What does the `<<` operator do when used on a Groovy List?

Accepted Answer

Appends an element to the list in place and returns the list

Answer

Performs a left bitwise shift on each element

Answer

Creates a new list with the element prepended

Answer

Merges two lists by interleaving their elements

Question 7

What Groovy feature allows a closure passed as the last argument to a method to be placed outside the parentheses?

Accepted Answer

Trailing closure syntax

Answer

Closure hoisting

Answer

Lambda promotion

Answer

Deferred closure evaluation