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Groovy / Metaprogramming

AST transform @ToString

Learn AST transform @ToString in Groovy through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

12 min read • Intermediate

AST transform @ToString is a focused Groovy lesson inside Metaprogramming. The example uses the construct named in the lesson directly rather than reusing a generic placeholder.

Trace the example from its inputs through AST transform @ToString 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-0057-7c0a6a6a47.groovy
groovy Try It Live 
def sample58 = [58, 59, 60]
println sample58.sum() // AST transform @ToString
Edge case / engineering note

For AST transform @ToString, 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

AST transform @ToString Mastery Check →
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AST transform @Immutable