Merge pull request quarkusio#42289 from mariofusco/gen_json_doc

Document reflection free Jackson serializers

docs/src/main/asciidoc/rest.adoc

@@ -1581,6 +1581,12 @@ public User userPrivate() {
 When the result the `userPublic` method is serialized, the `id` field will not be contained in the response as the `Public` view does not include it.
 The result of `userPrivate` however will include the `id` as expected when serialized.
 
+===== Reflection-free Jackson serialization
+
+Out-of-the-box Jackson serialization converts objects into their JSON representation by introspecting them through a heavy use of reflection. However, the general Quarkus philosophy is to avoid reflection as much as possible, often replacing it with build time code generation. For this reason it is possible to automatically generate at build time implementations of the Jackson `StdSerializer`, one for each class to be converted in JSON. These generated serializers can be subsequently used by Quarkus at runtime to perform the JSON serialization of the objects returned by a REST endpoint without any use of reflection.
+
+This feature is turned off by default, but it can be enabled by setting the configuration property `quarkus.rest.jackson.optimization.enable-reflection-free-serializers=true`.
+
 ===== Completely customized per method serialization/deserialization
 
 There are times when you need to completely customize the serialization/deserialization of a POJO on a per Jakarta REST method basis or on a per Jakarta REST resource basis. For such use cases, you can use the `@io.quarkus.resteasy.reactive.jackson.CustomSerialization` and `@io.quarkus.resteasy.reactive.jackson.CustomDeserialization` annotations in the REST method or in the REST resource at class level. These annotations allow you to fully configure the `com.fasterxml.jackson.databind.ObjectWriter`/`com.fasterxml.jackson.databind.ObjectReader`.

extensions/resteasy-reactive/rest-jackson/deployment/src/main/java/io/quarkus/resteasy/reactive/jackson/deployment/processor/JacksonOptimizationConfig.java

@@ -10,7 +10,7 @@
 /**
  * Jackson optimization configuration.
  */
-@ConfigMapping(prefix = "quarkus.jackson.optimization")
+@ConfigMapping(prefix = "quarkus.rest.jackson.optimization")
 @ConfigRoot(phase = ConfigPhase.BUILD_TIME)
 public interface JacksonOptimizationConfig {
 

extensions/resteasy-reactive/rest-jackson/deployment/src/test/java/io/quarkus/resteasy/reactive/jackson/deployment/test/SimpleJsonWithReflectionFreeSerializersTest.java

@@ -28,7 +28,7 @@ public JavaArchive get() {
  .addAsResource(new StringAsset("admin-expression=admin\n" +
  "user-expression=user\n" +
  "birth-date-roles=alice,bob\n" +
- "quarkus.jackson.optimization.enable-reflection-free-serializers=true\n"),
+ "quarkus.rest.jackson.optimization.enable-reflection-free-serializers=true\n"),
  "application.properties");
  }
  });