From ebfd1d5bfa9865c3b0456a8c4f9cba3da86f6182 Mon Sep 17 00:00:00 2001
From: Arne Limburg <arne@apache.org>
Date: Mon, 29 Jun 2026 19:07:50 +0200
Subject: [PATCH] JOHNZON-431: Add detection of annotations at class level for
 constructor parameters

---
 .../apache/johnzon/jsonb/JsonbAccessMode.java | 16 +++++--
 .../johnzon/jsonb/JsonbAdapterTest.java       | 48 +++++++++++++++++++
 2 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JsonbAccessMode.java b/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JsonbAccessMode.java
index 4ce308af3..ef0e70693 100644
--- a/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JsonbAccessMode.java
+++ b/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JsonbAccessMode.java
@@ -260,11 +260,11 @@ final boolean record = isRecord(clazz) || Meta.getAnnotation(clazz, JohnzonRecor
                                         .orElseGet(() -> naming.translateName(parameter.getName())) :
                                 naming.translateName(parameter.getName()));
 
-                final JsonbTypeAdapter adapter = getAnnotation(parameter, JsonbTypeAdapter.class);
-                final JsonbDateFormat dateFormat = getAnnotation(parameter, JsonbDateFormat.class);
-                final JsonbNumberFormat numberFormat = getAnnotation(parameter, JsonbNumberFormat.class);
+                final JsonbTypeAdapter adapter = getAnnotationOnParameterOrParameterType(parameter, JsonbTypeAdapter.class);
+                final JsonbDateFormat dateFormat = getAnnotationOnParameterOrParameterType(parameter, JsonbDateFormat.class);
+                final JsonbNumberFormat numberFormat = getAnnotationOnParameterOrParameterType(parameter, JsonbNumberFormat.class);
                 final JohnzonConverter johnzonConverter = getAnnotation(parameter, JohnzonConverter.class);
-                final JsonbTypeDeserializer deserializer = getAnnotation(parameter, JsonbTypeDeserializer.class);
+                final JsonbTypeDeserializer deserializer = getAnnotationOnParameterOrParameterType(parameter, JsonbTypeDeserializer.class);
                 if (adapter == null && dateFormat == null && numberFormat == null && johnzonConverter == null && deserializer == null) {
                     converters[i] = defaultConverters.get(parameter.getType());
                     itemConverters[i] = null;
@@ -1054,6 +1054,14 @@ private static <T extends Annotation> T getAnnotation(final Parameter param, fin
         return Meta.findMeta(param.getAnnotations(), api);
     }
 
+    private static <T extends Annotation> T getAnnotationOnParameterOrParameterType(final Parameter param, final Class<T> api) {
+        final T annotation = getAnnotation(param, api);
+        if (annotation != null) {
+            return annotation;
+        }
+        return Meta.getAnnotation(param.getType(), api);
+    }
+
     @Override
     public void clean(final Class<?> value) {
         if (Cleanable.class.isInstance(visibility)) {
diff --git a/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbAdapterTest.java b/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbAdapterTest.java
index e037ac4e1..34a4e230c 100644
--- a/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbAdapterTest.java
+++ b/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbAdapterTest.java
@@ -23,6 +23,9 @@
 import org.junit.Test;
 
 import jakarta.json.bind.adapter.JsonbAdapter;
+import jakarta.json.bind.annotation.JsonbCreator;
+import jakarta.json.bind.annotation.JsonbProperty;
+import jakarta.json.bind.annotation.JsonbTypeAdapter;
 
 import static org.junit.Assert.assertEquals;
 
@@ -43,6 +46,18 @@ public void testInheritedAdapterRecognized() {
         assertEquals("\"#336699\"", json);
     }
 
+    @Test
+    public void adapterAtConstructorParameterRecognized() {
+        // given
+        String json = "{\"innerValue\": \"value\"}";
+
+        // when
+        OuterObject object = jsonbRule.fromJson(json, OuterObject.class);
+
+        // then
+        assertEquals("value", object.innerObject.value);
+    }
+
     interface ValueType<T> {
         T value();
     }
@@ -76,4 +91,37 @@ public ColorId adaptFromJson(String s) throws Exception {
             return new ColorId(s);
         }
     }
+
+    public static class OuterObject {
+
+        private InnerObject innerObject;
+
+        @JsonbCreator
+        public OuterObject(@JsonbProperty("innerValue") InnerObject object) {
+            innerObject = object;
+        }
+    }
+
+    @JsonbTypeAdapter(InnerObjectAdapter.class)
+    static class InnerObject {
+
+        private String value;
+
+        public InnerObject(String value) {
+            this.value = value;
+        }
+    }
+
+    public static class InnerObjectAdapter implements JsonbAdapter<InnerObject, String> {
+
+        @Override
+        public String adaptToJson(InnerObject object) throws Exception {
+            return object.value;
+        }
+
+        @Override
+        public InnerObject adaptFromJson(String value) throws Exception {
+            return new InnerObject(value);
+        }
+    }
 }