Scanning Java annotations at runtime [closed]

Use org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider

API

A component provider that scans the classpath from a base package. It then applies exclude and include filters to the resulting classes to find candidates.

ClassPathScanningCandidateComponentProvider scanner =new ClassPathScanningCandidateComponentProvider(<DO_YOU_WANT_TO_USE_DEFALT_FILTER>);scanner.addIncludeFilter(new AnnotationTypeFilter(<TYPE_YOUR_ANNOTATION_HERE>.class));for (BeanDefinition bd : scanner.findCandidateComponents(<TYPE_YOUR_BASE_PACKAGE_HERE>))    System.out.println(bd.getBeanClassName());

And another solution is Google reflections.

Quick review:

• Spring solution is the way to go if you're using Spring. Otherwise it's a big dependency.
• Using ASM directly is a bit cumbersome.
• Using Java Assist directly is clunky too.
• Annovention is super lightweight and convenient. No maven integration yet.
• Google reflections pulls in Google collections. Indexes everything and then is super fast.

You can find classes with any given annotation with ClassGraph, as well as searching for other criteria of interest, e.g. classes that implement a given interface. (Disclaimer, I am the author of ClassGraph.) ClassGraph can build an abstract representation of the entire class graph (all classes, annotations, methods, method parameters, and fields) in memory, for all classes on the classpath, or for classes in whitelisted packages, and you can query that class graph however you want. ClassGraph supports more classpath specification mechanisms and classloaders than any other scanner, and also works seamlessly with the new JPMS module system, so if you base your code on ClassGraph, your code will be maximally portable. See the API here.