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Beyond Lombok: Modern Java Code Generation Tools
As Java developer, you are likely familiar with Lombok, the popular Java library that helps reduce boilerpate code. The magic happens in compile time when Lombok generates setter, getters, constructors, etc. The Lombok despite its powerfull and popularity not only player in Java code generation space. In this article, we will explore two other modern Java generation tools: MapStruct and Java Poet. I will try to explain how it works under the hood
Lombok: Annotation — based code generation
Let’s briefly discuss how Lombok works. Lombok relies on annotations to generate code at compile time. The Lombok’s annotation processor kicks in during compilation and generates the corresponding Java bytecode.
The Lombok utilize Java’s annotation processing API to hook into compilation process. During compliation it scans your source files for annotations and modifies the abstract syntax tree (AST) of your code to include generated methods. This steps occurs before the javac converts the AST to bytecode, so from compiler’s perspective, it’s as if you wrote the boilerplate code yourself.
While Lombok is excellent tool for reduceing boilerplate code, it has some pitfalls. The Lombok’s primarily focused on generating code within a single class.
