Bael-5645 - Scanning Java Annotations at Runtime (#12527)

* BAEL-5645 - Annotation scanners using Spring context, Spring core, reflections, java reflection, and Jandex libraries are implemented

* BAEL-5645 - Library versions are incremented in pom.xml

* BAEL-5645 - Some refactoring and indentation adjustments

* BAEL-5645 - Revert of annotation value in unit test

* BAEL-5645 - Merge with the latest remote version (after resolution of the conflicts)

* BAEL-5645 - Some refactoring due to review comments

Co-authored-by: elcimduran <elcim.duran@kboxglobal.com>

spring-boot-modules/spring-boot-libraries-2/src/main/java/com/baeldung/annotation/scanner/jandexlib/JandexScannerService.java

@@ -27,7 +27,9 @@ public class JandexScannerService implements SampleAnnotationScanner {
         try {
             final IndexReader reader = new IndexReader(appFile.getInputStream());
             Index jandexFile = reader.read();
-            final List<AnnotationInstance> appAnnotationList = jandexFile.getAnnotations(DotName.createSimple("com.baeldung.annotation.scanner.SampleAnnotation"));
+            final List<AnnotationInstance> appAnnotationList = jandexFile
+                .getAnnotations(DotName
+                    .createSimple("com.baeldung.annotation.scanner.SampleAnnotation"));
             List<String> annotatedMethods = new ArrayList<>();
             for (AnnotationInstance annotationInstance : appAnnotationList) {
                 if (annotationInstance.target()
@@ -48,7 +50,9 @@ public class JandexScannerService implements SampleAnnotationScanner {
         try {
             final IndexReader reader = new IndexReader(appFile.getInputStream());
             Index jandexFile = reader.read();
-            final List<AnnotationInstance> appAnnotationList = jandexFile.getAnnotations(DotName.createSimple("com.baeldung.annotation.scanner.SampleAnnotation"));
+            final List<AnnotationInstance> appAnnotationList = jandexFile
+                .getAnnotations(DotName
+                    .createSimple("com.baeldung.annotation.scanner.SampleAnnotation"));
             List<String> annotatedClasses = new ArrayList<>();
             for (AnnotationInstance annotationInstance : appAnnotationList) {
                 if (annotationInstance.target()

spring-boot-modules/spring-boot-libraries-2/src/main/java/com/baeldung/annotation/scanner/javareflectionlib/JavaReflectionsScannerService.java

@@ -1,5 +1,6 @@
 package com.baeldung.annotation.scanner.javareflectionlib;
 
+import java.lang.annotation.Annotation;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -37,9 +38,14 @@ public class JavaReflectionsScannerService implements SampleAnnotationScanner {
         try {
             Class<?> clazz = ClassLoader.getSystemClassLoader()
                 .loadClass("com.baeldung.annotation.scanner.SampleAnnotatedClass");
-            SampleAnnotation classAnnotation = clazz.getAnnotation(SampleAnnotation.class);
             List<String> annotatedClasses = new ArrayList<>();
-            annotatedClasses.add(classAnnotation.name());
+            Annotation[] classAnnotations = clazz.getAnnotations();
+            for (Annotation annotation : classAnnotations) {
+                if (annotation.annotationType()
+                    .equals(SampleAnnotation.class)) {
+                    annotatedClasses.add(((SampleAnnotation) annotation).name());
+                }
+            }
             return Collections.unmodifiableList(annotatedClasses);
         } catch (ClassNotFoundException e) {
             throw new UnexpectedScanException(e);

spring-boot-modules/spring-boot-libraries-2/src/main/java/com/baeldung/annotation/scanner/reflectionslib/ReflectionsScannerService.java

@@ -16,7 +16,8 @@ public class ReflectionsScannerService implements SampleAnnotationScanner {
     @Override
     public List<String> scanAnnotatedMethods() {
         Reflections reflections = new Reflections("com.baeldung.annotation.scanner");
-        Set<Method> methods = reflections.getMethodsAnnotatedWith(SampleAnnotation.class);
+        Set<Method> methods = reflections
+            .getMethodsAnnotatedWith(SampleAnnotation.class);
         return methods.stream()
             .map(method -> method.getAnnotation(SampleAnnotation.class)
                 .name())
@@ -26,7 +27,8 @@ public class ReflectionsScannerService implements SampleAnnotationScanner {
     @Override
     public List<String> scanAnnotatedClasses() {
         Reflections reflections = new Reflections("com.baeldung.annotation.scanner");
-        Set<Class<?>> types = reflections.getTypesAnnotatedWith(SampleAnnotation.class);
+        Set<Class<?>> types = reflections
+            .getTypesAnnotatedWith(SampleAnnotation.class);
         return types.stream()
             .map(clazz -> clazz.getAnnotation(SampleAnnotation.class)
                 .name())

spring-boot-modules/spring-boot-libraries-2/src/main/java/com/baeldung/annotation/scanner/springcontextlib/SpringContextAnnotationScannerService.java

@@ -17,7 +17,7 @@ import com.baeldung.annotation.scanner.SampleAnnotationScanner;
 import com.baeldung.annotation.scanner.ScanNotSupportedException;
 
 @Service
-public class SpringBeanAnnotationScannerService implements SampleAnnotationScanner {
+public class SpringContextAnnotationScannerService implements SampleAnnotationScanner {
     @Override
     public List<String> scanAnnotatedMethods() {
         throw new ScanNotSupportedException();
@@ -25,13 +25,16 @@ public class SpringBeanAnnotationScannerService implements SampleAnnotationScann
 
     @Override
     public List<String> scanAnnotatedClasses() {
-        ClassPathScanningCandidateComponentProvider provider = new ClassPathScanningCandidateComponentProvider(false);
+        ClassPathScanningCandidateComponentProvider provider =
+            new ClassPathScanningCandidateComponentProvider(false);
         provider.addIncludeFilter(new AnnotationTypeFilter(SampleAnnotation.class));
-        Set<BeanDefinition> beanDefs = provider.findCandidateComponents("com.baeldung.annotation.scanner");
+        Set<BeanDefinition> beanDefs = provider
+            .findCandidateComponents("com.baeldung.annotation.scanner");
         List<String> annotatedBeans = new ArrayList<>();
         for (BeanDefinition bd : beanDefs) {
             if (bd instanceof AnnotatedBeanDefinition) {
-                Map<String, Object> annotAttributeMap = ((AnnotatedBeanDefinition) bd).getMetadata()
+                Map<String, Object> annotAttributeMap = ((AnnotatedBeanDefinition) bd)
+                    .getMetadata()
                     .getAnnotationAttributes(SampleAnnotation.class.getCanonicalName());
                 annotatedBeans.add(annotAttributeMap.get("name")
                     .toString());

spring-boot-modules/spring-boot-libraries-2/src/main/java/com/baeldung/annotation/scanner/springcorelib/SpringCoreAnnotationScannerService.java

@@ -8,21 +8,24 @@ import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.stereotype.Service;
 import org.springframework.util.ClassUtils;
 
-import com.baeldung.annotation.scanner.SampleAnnotationScanner;
 import com.baeldung.annotation.scanner.SampleAnnotatedClass;
 import com.baeldung.annotation.scanner.SampleAnnotation;
+import com.baeldung.annotation.scanner.SampleAnnotationScanner;
 import com.baeldung.annotation.scanner.ScanNotSupportedException;
 
 @Service
 public class SpringCoreAnnotationScannerService implements SampleAnnotationScanner {
     @Override
     public List<String> scanAnnotatedMethods() {
-        final Class<?> userClass = ClassUtils.getUserClass(SampleAnnotatedClass.class);
-        return Arrays.stream(userClass.getMethods())
-            .filter(method -> AnnotationUtils.getAnnotation(method, SampleAnnotation.class) != null)
+        Class<?> userClass = ClassUtils.getUserClass(SampleAnnotatedClass.class);
+        List<String> annotatedMethods = Arrays.stream(userClass.getMethods())
+            .filter(method -> AnnotationUtils
+                .getAnnotation(method, SampleAnnotation.class) != null)
             .map(method -> method.getAnnotation(SampleAnnotation.class)
                 .name())
             .collect(Collectors.toList());
+
+        return annotatedMethods;
     }
 
     @Override

spring-boot-modules/spring-boot-libraries-2/src/test/java/com/baeldung/annotation/scanner/SampleAnnotationScannerUnitTest.java

@@ -28,7 +28,8 @@ public class SampleAnnotationScannerUnitTest {
 
         assertNotNull(annotatedClasses);
         assertEquals(4, annotatedClasses.size());
-        annotatedClasses.forEach(annotValue -> assertEquals("SampleAnnotatedClass", annotValue));
+        annotatedClasses.forEach(annotValue -> assertEquals("SampleAnnotatedClass",
+            annotValue));
     }
 
     @Test
@@ -41,7 +42,7 @@ public class SampleAnnotationScannerUnitTest {
 
         assertNotNull(annotatedMethods);
         assertEquals(3, annotatedMethods.size());
-        annotatedMethods.forEach(annotValue -> assertEquals("annotatedMethod", annotValue));
+        annotatedMethods.forEach(annotValue -> assertEquals("annotatedMethod",
+            annotValue));
     }
-
 }