mandrean opened a new issue, #3720: URL: https://github.com/apache/fory/issues/3720
## Search before asking - [x] I had searched in the [issues](https://github.com/apache/fory/issues) and found no similar issues. ## Version Apache Fory 1.0.0, Java serializer, `CompatibleMode.COMPATIBLE`. The warning is seen in a Java application when `scala.Product` is loadable from the runtime classpath. The application code and affected serialized classes are Java classes, not Scala classes. It is enough for the application to depend on some ordinary Java-facing library that happens to pull in Scala transitively. The application does not need to declare `org.scala-lang:scala-library` directly and does not need to use any Scala APIs. ## Component(s) Java ## Minimal reproduce step Create a small Maven project with Fory 1.0.0, Lombok, and any Java-facing dependency that brings `scala-library` onto the runtime classpath transitively. The Java code does not need to use Scala; `scala-library` only needs to be present transitively so `org.apache.fory.type.ScalaTypes.SCALA_AVAILABLE` becomes true. `pom.xml`: ```xml <project xmlns="http://maven.apache.org/POM/4.0.0"; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd";> <modelVersion>4.0.0</modelVersion> <groupId>repro</groupId> <artifactId>fory-lombok-default-repro</artifactId> <version>1.0-SNAPSHOT</version> <properties> <maven.compiler.release>17</maven.compiler.release> </properties> <dependencies> <dependency> <groupId>org.apache.fory</groupId> <artifactId>fory-core</artifactId> <version>1.0.0</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.36</version> <scope>provided</scope> </dependency> <!-- Used only as an example of a Java application dependency that brings scala-library transitively. --> <dependency> <groupId>org.apache.kafka</groupId> <artifactId>kafka_2.13</artifactId> <version>3.6.2</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-simple</artifactId> <version>2.0.12</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <version>3.3.0</version> </plugin> </plugins> </build> </project> ``` `src/main/java/repro/LombokDefaultRepro.java`: ```java package repro; import java.util.List; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Value; import org.apache.fory.Fory; import org.apache.fory.config.CompatibleMode; import org.apache.fory.config.Language; import org.apache.fory.logging.LoggerFactory; public class LombokDefaultRepro { @Value @Builder @AllArgsConstructor public static class JavaPojo { String id; @Builder.Default List<String> imageRelations = List.of(); } public static void main(String[] args) { LoggerFactory.useSlf4jLogging(true); Fory fory = Fory.builder() .withLanguage(Language.JAVA) .requireClassRegistration(false) .withCompatibleMode(CompatibleMode.COMPATIBLE) .build(); byte[] bytes = fory.serialize(JavaPojo.builder().id("1").build()); fory.deserialize(bytes, JavaPojo.class); } } ``` Run: ```bash mvn -q compile exec:java -Dexec.mainClass=repro.LombokDefaultRepro ``` Confirm that Scala is present transitively: ```bash mvn -q dependency:tree -Dincludes=org.scala-lang:scala-library ``` Expected dependency path: ```text repro:fory-lombok-default-repro:jar:1.0-SNAPSHOT \- org.apache.kafka:kafka_2.13:jar:3.6.2:compile \- org.scala-lang:scala-library:jar:2.13.11:compile ``` Lombok compiles `@Builder.Default` into a private static method whose name has the shape `$default$imageRelations()`: ```bash javap -classpath target/classes -private 'repro.LombokDefaultRepro$JavaPojo' ``` Relevant output: ```text private static java.util.List<java.lang.String> $default$imageRelations(); ``` If the Kafka dependency, or any other dependency that makes `scala.Product` loadable, is removed, the warning is not emitted because the Scala default-value branch is not enabled. ## What did you expect to see? No warning should be emitted for a plain Java class just because Scala is present somewhere on the runtime classpath. Fory's Scala default-value support should either only inspect Scala types, or it should only treat method names as Scala default methods when the suffix after `$default$` is numeric, such as `apply$default$1`. ## What did you see instead? During deserialization, Fory logs a warning from `DefaultValueUtils`: ```text WARN org.apache.fory.util.DefaultValueUtils - Error For input string: "imageRelations" finding default value for repro.LombokDefaultRepro$JavaPojo, default values support is disabled when deserializing object of type repro.LombokDefaultRepro$JavaPojo ``` This happens even though `JavaPojo` is a Java class and the repro does not call any Kafka or Scala APIs. The only Scala-related condition is that `scala.Product` is loadable from the classpath via a transitive dependency. ## Anything Else? The suspected path is: - `CompatibleSerializer` enables Scala default-value support when `ScalaTypes.SCALA_AVAILABLE` is true. - `ScalaTypes.SCALA_AVAILABLE` is global and becomes true when `scala.Product` can be loaded. - `DefaultValueUtils.ScalaDefaultValueSupport#getDefaultValuesForRegularScalaClass` scans all declared methods whose names contain `$default$`. - It then parses the substring after `$default$` as an integer. - Lombok `@Builder.Default` generates methods like `$default$imageRelations`, where the suffix is a Java field name, not a Scala argument index. This makes a transitive Scala dependency enough to produce warning noise for Java Lombok model classes. In practice this can happen just by adding a Java-facing library whose own dependency graph includes Scala, even if the application is otherwise pure Java. ## Are you willing to submit a PR? - [ ] I'm willing to submit a PR! -- This is an automated message from the Apache Git Service. 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