Add introspectionPackage property to the @introspected annotation

core/src/main/java/io/micronaut/core/annotation/Introspected.java

@@ -156,6 +156,13 @@
      */
     String withPrefix() default "with";
 
+    /**
+     * @return The package to write introspections to. By default, uses the class package.
+     * @since 3.9.0
+     */
+    @Experimental
+    String introspectionPackage() default "";
+
     /**
      * Allow pre-computed indexes for property lookups based on an annotation and a member.
      *

inject-java-test/src/test/groovy/io/micronaut/inject/visitor/beans/BeanIntrospectionSpec.groovy

@@ -82,6 +82,41 @@ class Test extends Auditable {
         bean.updatedAt != null
     }
 
+    void "test introspection can written to different package"() {
+        when:
+        def classLoader = buildClassLoader("test.Test", '''
+package test;
+
+import io.micronaut.core.annotation.Introspected;
+
+@Introspected(introspectionPackage = "test.introspections")
+public class Test {
+    private String name;
+    public Test(String name) {
+        this.name = name;
+    }
+    public String getName() {
+        return name;
+    }
+}
+
+''')
+        def introspectionName = 'test.introspections.$Test$Introspection'
+        def introspection = classLoader.loadClass(introspectionName).newInstance() as BeanIntrospection
+
+        then:
+        introspection != null
+        introspection.getProperty("name").isPresent()
+
+        when:
+        def introspectionRefName = 'test.introspections.$Test$IntrospectionRef'
+        def introspectionRef = classLoader.loadClass(introspectionRefName).newInstance() as BeanIntrospectionReference
+
+        then:
+        introspectionRef != null
+        introspectionRef.load() != null
+    }
+
     void "test generics in arrays don't stack overflow"() {
         given:
         def introspection = buildBeanIntrospection('arraygenerics.Test', '''
@@ -904,6 +939,37 @@ class Test {}
         applicationContext.close()
     }
 
+    void "test create bean introspection for external class with custom package"() {
+        given:
+        def classLoader = buildClassLoader('test.Test', '''
+package test;
+
+import io.micronaut.core.annotation.Introspected;
+import io.micronaut.inject.visitor.beans.OuterBean;
+
+@Introspected(classes=OuterBean.InnerBean.class, introspectionPackage="test.micronaut.intro")
+class Test {}
+''')
+
+        when:"the reference is loaded"
+        def reference = classLoader.loadClass('test.micronaut.intro.$Test$IntrospectionRef0').newInstance() as BeanIntrospectionReference
+
+        then:"the reference is valid"
+        notThrown(ClassNotFoundException)
+        reference.getBeanType() == OuterBean.InnerBean.class
+        reference.load() != null
+
+        print(classLoader)
+
+        when:"the introspection is loaded"
+        def introspectionName = 'test.micronaut.intro.$io_micronaut_inject_visitor_beans_OuterBean$InnerBean$Introspection'
+        def introspection = classLoader.loadClass(introspectionName).newInstance() as BeanIntrospection
+
+        then:"the introspection is valid"
+        notThrown(ClassNotFoundException)
+        introspection.getProperty("name").isPresent()
+    }
+
     void "test create bean introspection for interface"() {
         given:
         def context = buildContext('itfcetest.MyInterface','''

inject/src/main/java/io/micronaut/inject/beans/visitor/BeanIntrospectionWriter.java

@@ -128,12 +128,12 @@ final class BeanIntrospectionWriter extends AbstractAnnotationMetadataWriter {
      * @param classElement           The class element
      * @param beanAnnotationMetadata The bean annotation metadata
      */
-    BeanIntrospectionWriter(ClassElement classElement, AnnotationMetadata beanAnnotationMetadata) {
-        super(computeReferenceName(classElement.getName()), classElement, beanAnnotationMetadata, true);
+    BeanIntrospectionWriter(String introspectionPackage, ClassElement classElement, AnnotationMetadata beanAnnotationMetadata) {
+        super(computeReferenceName(introspectionPackage, classElement.getName()), classElement, beanAnnotationMetadata, true);
         final String name = classElement.getName();
         this.classElement = classElement;
         this.referenceWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
-        this.introspectionName = computeIntrospectionName(name);
+        this.introspectionName = computeShortIntrospectionName(introspectionPackage, name);
         this.introspectionType = getTypeReferenceForName(introspectionName);
         this.beanType = getTypeReferenceForName(name);
         this.dispatchWriter = new DispatchWriter(introspectionType, Type.getType(AbstractInitializableBeanIntrospection.class));
@@ -149,16 +149,17 @@ final class BeanIntrospectionWriter extends AbstractAnnotationMetadataWriter {
      * @param beanAnnotationMetadata The bean annotation metadata
      */
     BeanIntrospectionWriter(
+            String introspectionPackage,
             String generatingType,
             int index,
             ClassElement originatingElement,
             ClassElement classElement,
             AnnotationMetadata beanAnnotationMetadata) {
-        super(computeReferenceName(generatingType) + index, originatingElement, beanAnnotationMetadata, true);
+        super(computeReferenceName(introspectionPackage, generatingType) + index, originatingElement, beanAnnotationMetadata, true);
         final String className = classElement.getName();
         this.classElement = classElement;
         this.referenceWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
-        this.introspectionName = computeIntrospectionName(generatingType, className);
+        this.introspectionName = computeIntrospectionName(introspectionPackage, className);
         this.introspectionType = getTypeReferenceForName(introspectionName);
         this.beanType = getTypeReferenceForName(className);
         this.dispatchWriter = new DispatchWriter(introspectionType);
@@ -996,22 +997,19 @@ private void pushAnnotationMetadata(ClassWriter classWriter, GeneratorAdapter st
     }
 
     @NonNull
-    private static String computeReferenceName(String className) {
-        String packageName = NameUtils.getPackageName(className);
+    private static String computeReferenceName(String packageName, String className) {
         final String shortName = NameUtils.getSimpleName(className);
         return packageName + ".$" + shortName + REFERENCE_SUFFIX;
     }
 
     @NonNull
-    private static String computeIntrospectionName(String className) {
-        String packageName = NameUtils.getPackageName(className);
+    private static String computeShortIntrospectionName(String packageName, String className) {
         final String shortName = NameUtils.getSimpleName(className);
         return packageName + ".$" + shortName + INTROSPECTION_SUFFIX;
     }
 
     @NonNull
-    private static String computeIntrospectionName(String generatingName, String className) {
-        final String packageName = NameUtils.getPackageName(generatingName);
+    private static String computeIntrospectionName(String packageName, String className) {
         return packageName + ".$" + className.replace('.', '_') + INTROSPECTION_SUFFIX;
     }
 

inject/src/main/java/io/micronaut/inject/beans/visitor/IntrospectedTypeElementVisitor.java

@@ -180,6 +180,8 @@ private void processIntrospected(ClassElement element, VisitorContext context, A
         Introspected.AccessKind[] accessKinds = introspected.enumValues("accessKind", Introspected.AccessKind.class);
         Introspected.Visibility[] visibilities =
                 introspected.enumValues("visibility", Introspected.Visibility.class);
+        final String introspectionPackage = introspected.stringValue("introspectionPackage").orElse(element.getPackageName());
+
         if (ArrayUtils.isEmpty(accessKinds)) {
             accessKinds = DEFAULT_ACCESS_KIND;
         }
@@ -217,6 +219,7 @@ private void processIntrospected(ClassElement element, VisitorContext context, A
                                 ? element.getAnnotationMetadata()
                                 : new AnnotationMetadataHierarchy(element.getAnnotationMetadata(), typeMetadata);
                         final BeanIntrospectionWriter writer = new BeanIntrospectionWriter(
+                                introspectionPackage,
                                 element.getName(),
                                 index.getAndIncrement(),
                                 element,
@@ -251,6 +254,7 @@ private void processIntrospected(ClassElement element, VisitorContext context, A
                             continue;
                         }
                         final BeanIntrospectionWriter writer = new BeanIntrospectionWriter(
+                                introspectionPackage,
                                 element.getName(),
                                 j++,
                                 element,
@@ -275,6 +279,7 @@ private void processIntrospected(ClassElement element, VisitorContext context, A
         } else {
 
             final BeanIntrospectionWriter writer = new BeanIntrospectionWriter(
+                    introspectionPackage,
                     element,
                     metadata ? element.getAnnotationMetadata() : null
             );