We provide examples for learning and teaching Spoon in https://github.com/SpoonLabs/spoon-examples/. Don't hesitate to propose new examples as pull-request!

The 'HelloWorldProcessor' prints hello world with compile-time reflection.

Program Analysis

The CatchProcessor detects empty catch blocks.

The ReferenceProcessor detects circular references between packages.

This Factory example detects wrong uses of the factory pattern.

Program Transformation

The NotNullProcessor adds a not-null check for all method parameters.

The LogProcessor adds a log information when entering a method.

The MutationProcessor randomly mutates some parts of the abstract syntax tree for mutation testing.

Transformation with Templates

The RetryTemplate creates retriable methods in case of exceptions if annotated by @RetryOnFailure.

Transformation with Annotations

The Bound example adds runtime checks based on annotations

The Nton example introduces a Nton design pattern (extension of singleton but for N instances) into a target class. It inserts static fields, methods, and initializer code into constructors.

The Database access example shows how to use annotation processing to add persistence into a POJO.

The Visitor example implements a visitor pattern by automatically introducing an accept method in a visited type hierarchy.

The Field Access example implements a refactoring that introduces setters and getters for the fields annotated with the Access annotation and that replaces all the direct accesses to these fields by calls to its new getters and setters.


The Distributed Calculus example creates a fun new language for distributed computing using Java and Spoon.