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Version: dev

Configuration

This page covers Kotlin-specific Fory instance configuration and creation.

Xlang Setup​

Fory Kotlin follows the Java builder default: xlang mode with compatible schema evolution. Use this path for cross-language Kotlin payloads, schema IDL generated Kotlin models, and KSP-generated xlang serializers.

import org.apache.fory.kotlin.ForyKotlin

val fory = ForyKotlin.builder()
    .withXlang(true)
    .requireClassRegistration(true)
    .build()

Native Mode Setup​

For same-language Kotlin/JVM payloads that need native JVM object behavior, use native mode explicitly:

import org.apache.fory.kotlin.ForyKotlin

val fory = ForyKotlin.builder().withXlang(false)
    .requireClassRegistration(true)
    .build()

Thread Safety​

Fory instance creation is not cheap. Instances should be shared between multiple serializations.

Single-Thread Usage​

import org.apache.fory.Fory
import org.apache.fory.kotlin.ForyKotlin

object ForyHolder {
    val fory: Fory = ForyKotlin.builder()
        .withXlang(true)
        .requireClassRegistration(true)
        .build()
}

Multi-Thread Usage​

For multi-threaded applications, use ThreadSafeFory:

import org.apache.fory.ThreadSafeFory
import org.apache.fory.kotlin.ForyKotlin

object ForyHolder {
    val fory: ThreadSafeFory = ForyKotlin.builder()
        .withXlang(true)
        .requireClassRegistration(true)
        .buildThreadSafeFory()
}

Using Builder Methods​

// Thread-safe Fory
val fory: ThreadSafeFory = ForyKotlin.builder()
    .withXlang(true)
    .requireClassRegistration(true)
    .buildThreadSafeFory()

Configuration​

All configuration options from Fory Java are available. See Java Configuration for the complete list.

Common options for Kotlin native-mode payloads:

import org.apache.fory.kotlin.ForyKotlin

val fory = ForyKotlin.builder().withXlang(false)
    // Enable reference tracking for circular references
    .withRefTracking(true)
    // Same-schema optimization. Use only when every reader and writer
    // always uses the same Kotlin/JVM schema.
    .withCompatible(false)
    // Enable async compilation for better startup performance
    .withAsyncCompilation(true)
    // Compression options
    .withIntCompressed(true)
    .withLongCompressed(true)
    .build()

Compatible Mode​

Compatible mode is enabled by default through the Java builder in both xlang and native mode. Keep this default when models may evolve independently, when services deploy separately, or when xlang schemas are written by hand in different languages.

Use withCompatible(false) only when the class schema used to deserialize every payload is always the same as the class schema used to serialize it and you want faster serialization and smaller size. For xlang payloads, call withCompatible(false) only after verifying that every language uses the same schema, or when native types are generated from Fory schema IDL.

Security​

Kotlin uses the Java configuration surface. Keep class registration enabled for production and any untrusted payload source:

val fory = ForyKotlin.builder()
    .requireClassRegistration(true)
    .withMaxDepth(50)
    .withMaxTypeFields(512)
    .withMaxTypeMetaBytes(4096)
    .build()

Security-related configuration:

  • Keep requireClassRegistration(true) and register application classes or generated modules.
  • Use withMaxDepth(...) to reject unexpectedly deep object graphs.
  • Keep withMaxTypeFields(...), withMaxTypeMetaBytes(...), and the remote schema-version limits at their defaults unless the data is not malicious and a trusted peer sends larger metadata or many schema versions.
  • Follow Java Configuration for allow-listing and unknown-class controls.