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Questions tagged [annotation-processing]

An annotation processor is a plug-in for the Java compiler. An annotation processor can do such things as analyze declarations, cause compilation errors and generate new compilation units.

An annotation processor is a plug-in for the Java compiler.

An annotation processor is an instance of javax.annotation.processing.Processor whose process method is invoked during compilation.

Once invoked, the processor is then able to do such things as:

  • Analyze parts of the abstract syntax tree, primarily declarations via javax.lang.model.element and types via javax.lang.model.type.
  • Cause compilation errors and warnings (similar to how the @Override annotation works) via the Messager.
  • Generate new compilation units (i.e. source code files) via the Filer which are subsequently compiled.

Notes on the current limitations of annotation processors

  • Annotation processors may only generate new compilation units, not modify existing compilation units. Some annotation processors, such as Project Lombok, achieve the latter via undocumented internal Javac API.
  • The existing API in Java Platform SE is limited to only analyzing declarations, such as class declarations and method declarations. The Compiler Tree API exists, which allows one to analyze the full abstract syntax tree, but it's largely undocumented and not yet a part of SE.

Resources

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How to generate the JPA entity Metamodel?

In the spirit of type safety associated with the CriteriaQuery JPA 2.0 also has an API to support Metamodel representation of entities. Is anyone aware of a fully functional implementation of this API (to generate the Metamodel as opposed to…
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Java 6 annotation processing -- getting a class from an annotation

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Is it possible to use Lombok with Kotlin?

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How can I add a generated Source Folder to my Source Path in Gradle?

I use annotation processing. Therefore I use the apt plugin. It generates new java sources in build/source/apt. Here is my build.gradle: apply plugin: 'java' apply plugin: 'eclipse' apply plugin: 'apt' apply plugin: 'war' apply plugin: 'gwt' apply…
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Specifying order of annotation processors

I'm trying to run Dagger 2 as well as Lombok on my Java project. Lombok has to run first, of course, but whether it actually does seems to be up to chance. At first I suspected I could specify the order by the respective position of the library jars…
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I need to run an annotation processor on my project's sources. The annotation processor should not become a transitive dependency of the project since it's only needed for annotation processing and nothing else. Here is the complete (non-working)…
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I'm experimenting with java annotation processors. I'm able to write integration tests using the "JavaCompiler" (in fact I'm using "hickory" at the moment). I can run the compile process and analyse the output. The Problem: a single test runs for…
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Gradle deprecated annotation processor warnings for lombok

After upgrading to gradle 4.7, my previously warning-free build now emits this warning: The following annotation processors were detected on the compile classpath: 'lombok.launch.AnnotationProcessorHider$AnnotationProcessor' and…
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Android javax.annotation.processing Package missing

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Automatically generate .factorypath on project import when using Maven project in Eclipse IDE

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Annotation Processor in IntelliJ and Gradle

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Forward compatible Java 6 annotation processor and SupportedSourceVersion

I am trying out Java 7 for one project and getting warnings from annotation processors (Bindgen and Hibernate JPA modelgen) of this sort: warning: Supported source version 'RELEASE_6' from annotation processor…
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Annotation processor-generated Errors/warnings not showing in Eclipse editor or Problems view

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Code replacement with an annotation processor

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