Groovy Metaprogramming

Groovy metaprogramming tutorials. Runtime and compile-time techniques including MetaClass, ExpandoMetaClass, categories, mixins, and AST transforms.

Groovy Advanced AST Transforms – Part 2 with 10+ Examples

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Groovy advanced AST transforms beyond @ToString and @Canonical. Part 2 covers @TupleConstructor, @MapConstructor, @Delegate, @Memoized, @AutoClone, @Sortable, @Newify, and combining multiple transforms. “The best boilerplate is the boilerplate you never write. AST transformations are your compiler doing your chores.” Dierk König, Groovy in Action Last Updated: March 2026 | Tested on: Groovy 5.x, Java 17+ | Difficulty: Intermediate | Reading Time: 20 minutes This is Part 2 of our AST transformations series. Part 1 covered the essentials – @ToString, @EqualsAndHashCode, ... Read More

Groovy Custom Annotations – Create Your Own with 10 Tested Examples

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Groovy custom annotations are versatile. See 10 tested examples covering annotation declaration, retention policies, AST transformations, and runtime processing. “Annotations are metadata that give your code a voice – they tell the compiler, the runtime, and other developers what your intentions are without cluttering your logic.” Joshua Bloch, Effective Java Last Updated: March 2026 | Tested on: Groovy 4.x / 5.x, Java 11+ | Difficulty: Advanced | Reading Time: 18 minutes Groovy ships with a rich set of built-in annotations ... Read More

Groovy @Builder Annotation – Builder Pattern Made Easy with 10+ Examples

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Groovy builder pattern with the @Builder annotation with 10+ examples. DefaultStrategy, SimpleStrategy, ExternalStrategy, InitializerStrategy explained. “The builder pattern separates the construction of a complex object from its representation. Groovy’s @Builder does this without writing a single builder class.” Gang of Four, Design Patterns Last Updated: March 2026 | Tested on: Groovy 5.x, Java 17+ | Difficulty: Intermediate | Reading Time: 19 minutes When a class has many fields – some required, some optional – constructors become unwieldy and map-based construction ... Read More