title: Kotlin Setup sidebar_position: 11 id: kotlin license: | Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Fory Kotlin provides binary Object Serialization, standard JSON mapping, generated models, Fory gRPC, and Android support. It runs on Fory Java and supports Java 8 and later.

Verify the Toolchain

java -version
./gradlew --version
# or: mvn -version

Object Serialization

The repositories below resolve release coordinates from Maven Central and -SNAPSHOT coordinates from the Apache snapshot repository. Keep every Fory module on the same version:

repositories {
  maven("https://repository.apache.org/snapshots/") {
    mavenContent { snapshotsOnly() }
  }
  mavenCentral()
}

dependencies {
  implementation("org.apache.fory:fory-kotlin:1.7.0-SNAPSHOT")
}

Create src/main/kotlin/KotlinExample.kt:

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

data class User(val id: Long, val name: String)

fun main() {
    val fory: ThreadSafeFory = ForyKotlin.builder()
        .withXlang(true)
        .requireClassRegistration(true)
        .buildThreadSafeFory()
    fory.register(User::class.java, 1)

    val bytes = fory.serialize(User(1, "Alice"))
    val decoded = fory.deserialize(bytes) as User
    println(decoded.name)
}

If the project applies Gradle's application plugin, run its application task:

./gradlew run

Use xlang mode when a peer uses a different Fory implementation family; use native mode for data within the JVM Fory implementation family. Continue with Kotlin Object Serialization, xlang, or native mode.

Standard JSON

Fory JSON is a separate text format from binary Object Serialization. Add its optional Kotlin module when interoperating with ordinary JSON APIs, browsers, logs, or other JSON libraries:

dependencies {
  implementation("org.apache.fory:fory-json-kotlin:1.7.0-SNAPSHOT")
}

import org.apache.fory.json.kotlin.ForyJsonKotlin
import org.apache.fory.json.kotlin.jsonTypeRef

data class User(val id: Long, val name: String)

val json = ForyJsonKotlin.builder().build()
val userType = jsonTypeRef<User>()
val text = json.toJson(User(1, "Alice"), userType)
val decoded = json.fromJson(text, userType)

The runtime reads Kotlin/JVM metadata directly. Add fory-json-kotlin-ksp only to Android builds that use R8 or ProGuard; it emits exact retention rules for Kotlin @JsonType models and source-owned exact Mixins. Native Image uses the normal @ForyJsonProvider workflow. Continue with Kotlin JSON.

Other Capabilities