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Groovy / Closures

Closure return values

Learn Closure return values in Groovy through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

10 min read • Beginner

Closure return values is a focused Groovy lesson inside Closures. The example uses the construct named in the lesson directly rather than reusing a generic placeholder.

Trace the example from its inputs through Closure return values and identify the behavior that would change if that construct were removed or replaced. Pay attention to the language-specific rules shown by the syntax, because neighboring lessons intentionally exercise different mechanisms.

Topic-specific example

groovy-0024-1c8a37ae99.groovy
groovy Try It Live 
def multiply = { int a, int b -> a * b }
def timesTen = multiply.curry(10)
assert timesTen(4) == 40
assert [a:1,b:2].find { it.value == 2 }.key == "b"
Edge case / engineering note

For Closure return values, test one realistic boundary: empty data, invalid input, unavailable resources, lifetime/cleanup, type constraints, or concurrency timing where applicable. A successful happy path is not enough to prove the construct is used correctly.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Closure return values Mastery Check →
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Closure delegation