Java Annotation Processing (defined by JSR 269) is a standardized API for hooking into the Java compiler, allowing you to validate the code under compilation and generate additional (source or byte) code. This Awesome List aims at providing an overview of helpful resources around that API, including existing useful annotation processors, related presentations and blog posts, implementation best practices etc.
Existing annotation processors for different purposes
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dekorate - Generates manifests for Kubernetes/OpenShift.
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Dagger - Compile-time dependency injection framework for both Java and Android.
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derive4j - Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching, folds, optics and typeclasses.
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domino-jackson - Generates Jackson based JSON mappers where the same mapper can be used on the JVM/android or GWT client Javascript code.
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domino-rest - Generates rest clients from JaxRs compatible interfaces.
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Duzzt - Duzzt - Annotation-based Embedded DSL Generator for Java.
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Google Auto - A collection of source code generators for Java.
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Gson Path - A Java annotation processor library which generates gson type adapters using basic JsonPath style annotations.
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Hibernate Validator annotation processor - Compile-time checking of Bean Validation constraints.
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JPA Static Metamodel Generator - Creates JPA 2 static metamodel classes.
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Immutables - Java annotation processors to generate simple, safe and consistent value objects.
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MapStruct - Compile-time generator for type-safe bean-to-bean mapping code.
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Micronaut - A modern full-stack framework for building modular, easily testable microservice and serverless applications.
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Sundrio - A collection of apt-based code generating tools, including advanced builder generator, dsl generator, velocity transformer and etc.
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Viper - A generator and a framework for injecting configurations via the java EE’s CDI. Put all your configuration keys in an enum, and make viper inject the configurations in your beans.
Annotation processors specific to Android development
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Butter Knife - Bind Android views and callbacks to fields and methods.
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Parceler - Android Parcelables made easy through code generation.
Useful tools and libraries for implementing annotation processors
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Compile Testing - Testing tools for javac and annotation processors.
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JavaPoet - A Java API for generating .java source files.
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Hickory - An annotation processor for generating "prisms", allowing to access known annotation types without class references.
APIs and tools going beyond what’s doable with JSR 269
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Spoon - Source Code Analysis and Transformation for Java (allows for AST modifications, too)
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javac Plug-in API (allows for full AST inspection)
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Project Lombok - Generates boilerplate Java code like getters/setters and equals/hashCode methods.