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

`@Immutable` makes all fields final, generates a tuple constructor, and provides `equals`, `hashCode`, and `toString` implementations.

Question 2

What does `@CompileStatic` do in Groovy?

Accepted Answer

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

Answer

`@CompileStatic` opts a class or method out of dynamic dispatch, enabling full static type checking and better runtime performance.

Question 3

In Groovy, what is a GString?

Accepted Answer

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

Answer

GStrings are Groovy string literals delimited by double quotes that allow expression interpolation via `${}` syntax.

Question 4

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

Accepted Answer

reduce/fold

Answer

`inject` accumulates a result by applying a closure to each element along with a running accumulator, equivalent to a fold/reduce operation.

Question 5

How does Groovy handle operator overloading?

Accepted Answer

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

Answer

Groovy maps operators to conventional method names — defining `plus(other)` on a class enables the `+` operator for that class.

Groovy and Grails Practice Test