Java Annotation Scanning

DemoAnnotationProcessorApplication.java

package de.fredlahde.demoannotationprocessor;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.core.type.filter.AnnotationTypeFilter;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Retention(RetentionPolicy.RUNTIME)
@interface Bar {
    String getBar();
}

@SpringBootApplication
public class DemoAnnotationProcessorApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoAnnotationProcessorApplication.class, args);
    }

    @Bean
    public CommandLineRunner clr() {
        return args -> {
            ClassPathScanningCandidateComponentProvider provider = new ClassPathScanningCandidateComponentProvider(false);

            provider.addIncludeFilter(new AnnotationTypeFilter(Bar.class));

            for (BeanDefinition bd : provider.findCandidateComponents("de.fredlahde")) {
                //noinspection unchecked
                Class<? extends Bar> cls = (Class<? extends Bar>) getClass().getClassLoader().loadClass(bd.getBeanClassName());
                String val = cls.getAnnotation(Bar.class).getBar();
                System.out.println(val);
            }
        };
    }
}

@Bar(getBar = "foobar")
class Foo {

}