import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;

@Controller("/hello") // (1)
public class HelloController {

    @Get(produces = MediaType.TEXT_PLAIN) // (2)
    public String index() {
        return "Hello World"; // (3)
    }
}

import io.micronaut.http.MediaType
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get

@Controller('/hello') // (1)
class HelloController {

    @Get(produces = MediaType.TEXT_PLAIN) // (2)
    String index() {
        'Hello World' // (3)
    }
}

import io.micronaut.http.MediaType
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get

@Controller("/hello") // (1)
class HelloController {

    @Get(produces = [MediaType.TEXT_PLAIN]) // (2)
    fun index(): String {
        return "Hello World" // (3)
    }
}

import io.micronaut.runtime.Micronaut;

public class Application {

    public static void main(String[] args) {
        Micronaut.run(Application.class);
    }
}

import io.micronaut.runtime.Micronaut

class Application {

    static void main(String... args) {
        Micronaut.run Application
    }
}

import io.micronaut.runtime.Micronaut

object Application {

    @JvmStatic
    fun main(args: Array<String>) {
        Micronaut.run(Application.javaClass)
    }
}

import io.micronaut.http.HttpRequest;
import io.micronaut.http.client.HttpClient;
import io.micronaut.http.client.annotation.Client;
import io.micronaut.runtime.server.EmbeddedServer;
import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

import jakarta.inject.Inject;

import static org.junit.jupiter.api.Assertions.assertEquals;

@MicronautTest
public class HelloControllerSpec {

    @Inject
    EmbeddedServer server; // (1)

    @Inject
    @Client("/")
    HttpClient client; // (2)

    @Test
    void testHelloWorldResponse() {
        String response = client.toBlocking() // (3)
                .retrieve(HttpRequest.GET("/hello"));
        assertEquals("Hello World", response); // (4)
    }
}

import io.micronaut.http.HttpRequest
import io.micronaut.http.client.HttpClient
import io.micronaut.http.client.annotation.Client
import io.micronaut.runtime.server.EmbeddedServer
import io.micronaut.test.extensions.spock.annotation.MicronautTest
import spock.lang.Specification

import jakarta.inject.Inject

@MicronautTest
class HelloControllerSpec extends Specification {

    @Inject
    EmbeddedServer embeddedServer // (1)

    @Inject
    @Client("/")
    HttpClient client // (2)

    void "test hello world response"() {
        expect:
            client.toBlocking() // (3)
                    .retrieve(HttpRequest.GET('/hello')) == "Hello World" // (4)
    }
}

import io.micronaut.http.client.HttpClient
import io.micronaut.http.client.annotation.Client
import io.micronaut.runtime.server.EmbeddedServer
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Test
import jakarta.inject.Inject

@MicronautTest
class HelloControllerSpec {

    @Inject
    lateinit var server: EmbeddedServer // (1)

    @Inject
    @field:Client("/")
    lateinit var client: HttpClient // (2)

    @Test
    fun testHelloWorldResponse() {
        val rsp: String = client.toBlocking() // (3)
                .retrieve("/hello")
        assertEquals("Hello World", rsp) // (4)
    }
}

import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Get;
import io.micronaut.http.client.annotation.Client;
import org.reactivestreams.Publisher;
import io.micronaut.core.async.annotation.SingleResult;

@Client("/hello") // (1)
public interface HelloClient {

    @Get(consumes = MediaType.TEXT_PLAIN) // (2)
    @SingleResult
    Publisher<String> hello(); // (3)
}

import io.micronaut.http.annotation.Get
import io.micronaut.http.client.annotation.Client
import org.reactivestreams.Publisher
import io.micronaut.core.async.annotation.SingleResult

@Client("/hello") // (1)
interface HelloClient {

    @Get(consumes = MediaType.TEXT_PLAIN) // (2)
    @SingleResult
    Publisher<String> hello() // (3)
}

import io.micronaut.http.MediaType
import io.micronaut.http.annotation.Get
import io.micronaut.http.client.annotation.Client
import io.micronaut.core.async.annotation.SingleResult
import org.reactivestreams.Publisher

@Client("/hello") // (1)
interface HelloClient {

    @Get(consumes = [MediaType.TEXT_PLAIN]) // (2)
    @SingleResult
    fun hello(): Publisher<String>  // (3)
}

import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

import jakarta.inject.Inject;
import reactor.core.publisher.Mono;

import static org.junit.jupiter.api.Assertions.assertEquals;

@MicronautTest // (1)
public class HelloClientSpec {

    @Inject
    HelloClient client; // (2)

    @Test
    public void testHelloWorldResponse() {
        assertEquals("Hello World", Mono.from(client.hello()).block());// (3)
    }
}

import io.micronaut.test.extensions.spock.annotation.MicronautTest
import reactor.core.publisher.Mono
import spock.lang.Specification

import jakarta.inject.Inject

@MicronautTest // (1)
class HelloClientSpec extends Specification {

    @Inject HelloClient client // (2)

    void "test hello world response"() {
        expect:
        Mono.from(client.hello()).block() == "Hello World" // (3)
    }

}

import io.micronaut.context.annotation.Property
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Test
import jakarta.inject.Inject
import reactor.core.publisher.Mono


@MicronautTest // (1)
class HelloClientSpec {

    @Inject
    lateinit var client: HelloClient // (2)

    @Test
    fun testHelloWorldResponse() {
        assertEquals("Hello World", Mono.from(client.hello()).block())// (3)
    }
}

public interface Engine { // (1)
    int getCylinders();
    String start();
}

@Singleton// (2)
public class V8Engine implements Engine {
    private int cylinders = 8;

    @Override
    public String start() {
        return "Starting V8";
    }

    @Override
    public int getCylinders() {
        return cylinders;
    }

    public void setCylinders(int cylinders) {
        this.cylinders = cylinders;
    }
}

@Singleton
public class Vehicle {
    private final Engine engine;

    public Vehicle(Engine engine) {// (3)
        this.engine = engine;
    }

    public String start() {
        return engine.start();
    }
}

interface Engine { // (1)
    int getCylinders()
    String start()
}

@Singleton // (2)
class V8Engine implements Engine {
    int cylinders = 8

    @Override
    String start() {
        "Starting V8"
    }
}

@Singleton
class Vehicle {
    final Engine engine

    Vehicle(Engine engine) { // (3)
        this.engine = engine
    }

    String start() {
        engine.start()
    }
}

interface Engine {
    // (1)
    val cylinders: Int

    fun start(): String
}

@Singleton// (2)
class V8Engine : Engine {

    override var cylinders = 8

    override fun start(): String {
        return "Starting V8"
    }
}

@Singleton
class Vehicle(private val engine: Engine) { // (3)
    fun start(): String {
        return engine.start()
    }
}

final ApplicationContext context = ApplicationContext.run();
Vehicle vehicle = context.getBean(Vehicle.class);
System.out.println(vehicle.start());

ApplicationContext context = ApplicationContext.run()
Vehicle vehicle = context.getBean(Vehicle)
println vehicle.start()

val context = ApplicationContext.run()
val vehicle = context.getBean(Vehicle::class.java)
println(vehicle.start())

package io.micronaut.docs.ioc.injection.ctor;

import io.micronaut.core.annotation.Creator;
import jakarta.inject.Inject;
import jakarta.inject.Singleton;

@Singleton
class Vehicle {
    private final Engine engine;

    @Inject // (1)
    Vehicle(Engine engine) {
        this.engine = engine;
    }

    Vehicle() {
        this.engine = Engine.create(6);
    }

    void start() {
        engine.start();
    }
}

@Singleton
record Engine(int cylinders) {

    @Creator // (2)
    static Engine getDefault() {
        return new Engine(8);
    }

    static Engine create(int cylinders) {
        return new Engine(cylinders);
    }

    void start() {
        System.out.println("Vrooom! " + cylinders);
    }
}

package io.micronaut.docs.ioc.injection.ctor

import io.micronaut.core.annotation.Creator
import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
class Vehicle {
    private final Engine engine

    @Inject // (1)
    Vehicle(Engine engine) {
        this.engine = engine
    }

    Vehicle() {
        this.engine = Engine.create(6)
    }

    void start() {
        engine.start()
    }
}

@Singleton
record Engine(int cylinders) {

    @Creator // (2)
    static Engine getDefault() {
        return new Engine(8)
    }

    static Engine create(int cylinders) {
        return new Engine(cylinders)
    }

    void start() {
        println("Vrooom! $cylinders")
    }
}

package io.micronaut.docs.ioc.injection.ctor

import io.micronaut.core.annotation.Creator
import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
class Vehicle {
    private val engine: Engine

    @Inject // (1)
    constructor(engine: Engine) {
        this.engine = engine
    }

    constructor() {
        this.engine = Engine.create(6)
    }

    fun start() {
        engine.start()
    }
}

@Singleton
data class Engine(val cylinders: Int) {
    fun start() {
        println("Vrooom! $cylinders")
    }

    companion object {
        @Creator // (2)
        fun getDefault() : Engine
             = Engine(8)

        fun create(cylinders: Int): Engine {
            return Engine(cylinders)
        }
    }
}

package io.micronaut.docs.ioc.injection.field;

import jakarta.inject.Inject;
import jakarta.inject.Singleton;

@Singleton
class Vehicle {
    @Inject Engine engine; // (1)

    void start() {
        engine.start();
    }
}

@Singleton
class Engine {
    void start() {
        System.out.println("Vrooom!" );
    }
}

package io.micronaut.docs.ioc.injection.field

import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
class Vehicle {
    @Inject Engine engine // (1)

    void start() {
        engine.start()
    }
}

@Singleton
class Engine {
    void start() {
        println("Vrooom!" )
    }
}

package io.micronaut.docs.ioc.injection.field

import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
internal class Vehicle {
    @Inject
    var engine: Engine? = null // (1)

    fun start() {
        engine!!.start()
    }
}

@Singleton
class Engine {
    fun start() {
        println("Vrooom!")
    }
}

package io.micronaut.docs.ioc.injection.method;

import jakarta.inject.Inject;
import jakarta.inject.Singleton;

@Singleton
class Vehicle {
    private Engine engine;

    @Inject // (1)
    void initialize(Engine engine) {
        this.engine = engine;
    }

    void start() {
        engine.start();
    }
}

@Singleton
class Engine {
    void start() {
        System.out.println("Vrooom!" );
    }
}

package io.micronaut.docs.ioc.injection.method

import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
class Vehicle {
    private Engine engine

    @Inject // (1)
    void initialize(Engine engine) {
        this.engine = engine
    }

    void start() {
        engine.start()
    }
}

@Singleton
class Engine {
    void start() {
        println("Vrooom!")
    }
}

package io.micronaut.docs.ioc.injection.method

import jakarta.inject.Inject
import jakarta.inject.Singleton

@Singleton
internal class Vehicle {
    private var engine: Engine? = null

    @Inject
    fun initialize(engine: Engine) {
        this.engine = engine
    }

    fun start() {
        engine!!.start()
    }
}

@Singleton
internal class Engine {
    fun start() {
        println("Vrooom!")
    }
}

package io.micronaut.docs.ioc.injection.nullable;

import io.micronaut.core.annotation.Nullable;
import jakarta.inject.Inject;
import jakarta.inject.Singleton;

@Singleton
class Vehicle {
    private final Engine engine;

    Vehicle(@Nullable Engine engine) { // (1)
        this.engine = engine != null ? engine : Engine.create(6); // (2)
    }
    void start() {
        engine.start();
    }

    public Engine getEngine() {
        return engine;
    }
}

record Engine(int cylinders) {

    static Engine create(int cylinders) {
        return new Engine(cylinders);
    }

    void start() {
        System.out.println("Vrooom! " + cylinders);
    }
}

package io.micronaut.docs.ioc.injection.nullable

import io.micronaut.core.annotation.Nullable
import jakarta.inject.Singleton

@Singleton
class Vehicle {
    private final Engine engine

    Vehicle(@Nullable Engine engine) { // (1)
        this.engine = engine ?: Engine.create(6) // (2)
    }
    void start() {
        engine.start()
    }
}

record Engine(int cylinders) {

    static Engine create(int cylinders) {
        return new Engine(cylinders)
    }

    void start() {
        println("Vrooom! $cylinders")
    }
}

package io.micronaut.docs.ioc.injection.nullable

import jakarta.inject.Singleton

@Singleton
class Vehicle(engine: Engine?) { // (1)
    private val engine = engine ?: Engine.create(6) // (2)
    fun start() {
        engine.start()
    }
}

data class Engine(val cylinders: Int) {
    fun start() {
        println("Vrooom! $cylinders")
    }

    companion object {
        fun create(cylinders: Int): Engine {
            return Engine(cylinders)
        }
    }
}

@Singleton
public class V8Engine implements Engine {  // (3)
    @Override
    public String start() {
        return "Starting V8";
    }

    @Override
    public int getCylinders() {
        return 8;
    }

}

@Singleton
class V8Engine implements Engine { // (3)
    int cylinders = 8

    @Override
    String start() {
        "Starting V8"
    }
}

@Singleton
class V8Engine : Engine {

    override var cylinders: Int = 8

    override fun start(): String {
        return "Starting V8"
    }

}

@Singleton
@Bean(typed = Engine.class) // (1)
public class V8Engine implements Engine {  // (2)
    @Override
    public String start() {
        return "Starting V8";
    }

    @Override
    public int getCylinders() {
        return 8;
    }
}

@Singleton
@Bean(typed = Engine) // (1)
class V8Engine implements Engine {  // (2)
    @Override
    String start() { "Starting V8" }

    @Override
    int getCylinders() { 8 }
}

@Singleton
@Bean(typed = [Engine::class]) // (1)
class V8Engine : Engine { // (2)
    override fun start(): String {
        return "Starting V8"
    }

    override val cylinders: Int = 8
}

@MicronautTest
public class EngineSpec {
    @Inject
    BeanContext beanContext;

    @Test
    public void testEngine() {
        assertThrows(NoSuchBeanException.class, () ->
                beanContext.getBean(V8Engine.class) // (1)
        );
        final Engine engine = beanContext.getBean(Engine.class); // (2)
        assertTrue(engine instanceof V8Engine);
    }
}

class EngineSpec extends Specification {
    @Shared @AutoCleanup
    ApplicationContext beanContext = ApplicationContext.run()

    void 'test engine'() {
        when:'the class is looked up'
        beanContext.getBean(V8Engine) // (1)

        then:'a no such bean exception is thrown'
        thrown(NoSuchBeanException)

        and:'it is possible to lookup by the typed interface'
        beanContext.getBean(Engine) instanceof V8Engine // (2)
    }
}

@MicronautTest
class EngineSpec {
    @Inject
    lateinit var beanContext: BeanContext

    @Test
    fun testEngine() {
        assertThrows(NoSuchBeanException::class.java) {
            beanContext.getBean(V8Engine::class.java) // (1)
        }

        val engine = beanContext.getBean(Engine::class.java) // (2)
        assertTrue(engine is V8Engine)
    }
}

@Refreshable // (1)
static class WeatherService {
    private String forecast;

    @PostConstruct
    public void init() {
        forecast = "Scattered Clouds " + new SimpleDateFormat("dd/MMM/yy HH:mm:ss.SSS").format(new Date());// (2)
    }

    public String latestForecast() {
        return forecast;
    }
}

@Refreshable // (1)
static class WeatherService {

    String forecast

    @PostConstruct
    void init() {
        forecast = "Scattered Clouds ${new SimpleDateFormat("dd/MMM/yy HH:mm:ss.SSS").format(new Date())}" // (2)
    }

    String latestForecast() {
        return forecast
    }
}

@Refreshable // (1)
open class WeatherService {
    private var forecast: String? = null

    @PostConstruct
    open fun init() {
        forecast = "Scattered Clouds " + SimpleDateFormat("dd/MMM/yy HH:mm:ss.SSS").format(Date())// (2)
    }

    open fun latestForecast(): String? {
        return forecast
    }
}

applicationContext.publishEvent(new RefreshEvent());

applicationContext.publishEvent(new RefreshEvent())

applicationContext.publishEvent(RefreshEvent())

import io.micronaut.context.annotation.Requires;

import jakarta.inject.Singleton;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Requires(classes = Car.class) // (1)
@Singleton // (2)
@Documented
@Retention(RUNTIME)
public @interface Driver {
}

import io.micronaut.context.annotation.Requires

import jakarta.inject.Singleton
import java.lang.annotation.Documented
import java.lang.annotation.Retention

import static java.lang.annotation.RetentionPolicy.RUNTIME

@Requires(classes = Car.class) // (1)
@Singleton // (2)
@Documented
@Retention(RUNTIME)
@interface Driver {
}

import io.micronaut.context.annotation.Requires
import jakarta.inject.Singleton
import kotlin.annotation.AnnotationRetention.RUNTIME

@Requires(classes = [Car::class]) // (1)
@Singleton // (2)
@MustBeDocumented
@Retention(RUNTIME)
annotation class Driver

@Requires(classes = Car.class)
@DefaultScope(Singleton.class) (1)
@Documented
@Retention(RUNTIME)
public @interface Driver {
}

@Requires(classes = Car.class)
@DefaultScope(Singleton.class) (1)
@Documented
@Retention(RUNTIME)
@interface Driver {
}

@Requires(classes = [Car::class])
@DefaultScope(Singleton::class) (1)
@Documented
@Retention(RUNTIME)
annotation class Driver

@Singleton
class CrankShaft {
}

class V8Engine implements Engine {
    private final int cylinders = 8;
    private final CrankShaft crankShaft;

    public V8Engine(CrankShaft crankShaft) {
        this.crankShaft = crankShaft;
    }

    @Override
    public String start() {
        return "Starting V8";
    }
}

@Factory
class EngineFactory {

    @Singleton
    Engine v8Engine(CrankShaft crankShaft) {
        return new V8Engine(crankShaft);
    }
}

@Singleton
class CrankShaft {
}

class V8Engine implements Engine {
    final int cylinders = 8
    final CrankShaft crankShaft

    V8Engine(CrankShaft crankShaft) {
        this.crankShaft = crankShaft
    }

    @Override
    String start() {
        "Starting V8"
    }
}

@Factory
class EngineFactory {

    @Singleton
    Engine v8Engine(CrankShaft crankShaft) {
        new V8Engine(crankShaft)
    }
}

@Singleton
internal class CrankShaft

internal class V8Engine(private val crankShaft: CrankShaft) : Engine {
    private val cylinders = 8

    override fun start(): String {
        return "Starting V8"
    }
}

@Factory
internal class EngineFactory {

    @Singleton
    fun v8Engine(crankShaft: CrankShaft): Engine {
        return V8Engine(crankShaft)
    }
}

@Singleton
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
public class JdbcBookService implements BookService {

    DataSource dataSource;

    public JdbcBookService(DataSource dataSource) {
        this.dataSource = dataSource;
    }

@Singleton
@Requires(beans = DataSource)
@Requires(property = "datasource.url")
class JdbcBookService implements BookService {

    DataSource dataSource

@Singleton
@Requirements(Requires(beans = [DataSource::class]), Requires(property = "datasource.url"))
class JdbcBookService(internal var dataSource: DataSource) : BookService {

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.PACKAGE, ElementType.TYPE})
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
public @interface RequiresJdbc {
}

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target([ElementType.PACKAGE, ElementType.TYPE])
@Requires(beans = DataSource)
@Requires(property = "datasource.url")
@interface RequiresJdbc {
}

@Documented
@Retention(AnnotationRetention.RUNTIME)
@Target(AnnotationTarget.CLASS, AnnotationTarget.FILE)
@Requirements(Requires(beans = [DataSource::class]), Requires(property = "datasource.url"))
annotation class RequiresJdbc

@Singleton
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
public class JdbcBookService implements BookService {

    DataSource dataSource;

    public JdbcBookService(DataSource dataSource) {
        this.dataSource = dataSource;
    }

@Singleton
@Requires(beans = DataSource)
@Requires(property = "datasource.url")
class JdbcBookService implements BookService {

    DataSource dataSource

@Singleton
@Requirements(Requires(beans = [DataSource::class]), Requires(property = "datasource.url"))
class JdbcBookService(internal var dataSource: DataSource) : BookService {

@Replaces(JdbcBookService.class) // (1)
@Singleton
public class MockBookService implements BookService {

    Map<String, Book> bookMap = new LinkedHashMap<>();

    @Override
    public Book findBook(String title) {
        return bookMap.get(title);
    }
}

@Replaces(JdbcBookService.class) // (1)
@Singleton
class MockBookService implements BookService {

    Map<String, Book> bookMap = [:]

    @Override
    Book findBook(String title) {
        bookMap.get(title)
    }
}

@Replaces(JdbcBookService::class) // (1)
@Singleton
class MockBookService : BookService {

    var bookMap: Map<String, Book> = LinkedHashMap()

    override fun findBook(title: String): Book? {
        return bookMap[title]
    }
}

public class V8Engine implements Engine {
    private final int cylinders = 8;
    private double rodLength; // (1)

    public V8Engine(double rodLength) {
        this.rodLength = rodLength;
    }

    @Override
    public String start() {
        return "Starting V" + getCylinders() + " [rodLength=" + getRodLength() + ']';
    }

    @Override
    public final int getCylinders() {
        return cylinders;
    }

    public double getRodLength() {
        return rodLength;
    }

    public void setRodLength(double rodLength) {
        this.rodLength = rodLength;
    }
}

@Factory
public class EngineFactory {

    private V8Engine engine;
    private double rodLength = 5.7;

    @PostConstruct
    public void initialize() {
        engine = new V8Engine(rodLength); // (2)
    }

    @Singleton
    public Engine v8Engine() {
        return engine;// (3)
    }

    public void setRodLength(double rodLength) {
        this.rodLength = rodLength;
    }
}

@Singleton
public class EngineInitializer implements BeanInitializedEventListener<EngineFactory> { // (4)
    @Override
    public EngineFactory onInitialized(BeanInitializingEvent<EngineFactory> event) {
        EngineFactory engineFactory = event.getBean();
        engineFactory.setRodLength(6.6);// (5)
        return engineFactory;
    }
}

class V8Engine implements Engine {
    final int cylinders = 8
    double rodLength // (1)

    @Override
    String start() {
        return "Starting V$cylinders [rodLength=$rodLength]"
    }
}

@Factory
class EngineFactory {
    private V8Engine engine
    double rodLength = 5.7

    @PostConstruct
    void initialize() {
        engine = new V8Engine(rodLength: rodLength) // (2)
    }

    @Singleton
    Engine v8Engine() {
        return engine // (3)
    }
}

@Singleton
class EngineInitializer implements BeanInitializedEventListener<EngineFactory> { // (4)
    @Override
    EngineFactory onInitialized(BeanInitializingEvent<EngineFactory> event) {
        EngineFactory engineFactory = event.bean
        engineFactory.rodLength = 6.6 // (5)
        return engineFactory
    }
}

class V8Engine(var rodLength: Double) : Engine {  // (1)

    override val cylinders = 8

    override fun start(): String {
        return "Starting V$cylinders [rodLength=$rodLength]"
    }
}

@Factory
class EngineFactory {

    private var engine: V8Engine? = null
    private var rodLength = 5.7

    @PostConstruct
    fun initialize() {
        engine = V8Engine(rodLength) // (2)
    }

    @Singleton
    fun v8Engine(): Engine? {
        return engine// (3)
    }

    fun setRodLength(rodLength: Double) {
        this.rodLength = rodLength
    }
}

@Singleton
class EngineInitializer : BeanInitializedEventListener<EngineFactory> { // (4)
    override fun onInitialized(event: BeanInitializingEvent<EngineFactory>): EngineFactory {
        val engineFactory = event.bean
        engineFactory.setRodLength(6.6) // (5)
        return engineFactory
    }
}

import io.micronaut.core.annotation.Introspected;

@Introspected
public class Person {

    private String name;
    private int age = 18;

    public Person(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

import groovy.transform.Canonical
import io.micronaut.core.annotation.Introspected

@Introspected
@Canonical
class Person {

    String name
    int age = 18

    Person(String name) {
        this.name = name
    }
}

import io.micronaut.core.annotation.Introspected

@Introspected
data class Person(var name : String) {
    var age : Int = 18
}

final BeanIntrospection<Person> introspection = BeanIntrospection.getIntrospection(Person.class); // (1)
Person person = introspection.instantiate("John"); // (2)
System.out.println("Hello " + person.getName());

final BeanProperty<Person, String> property = introspection.getRequiredProperty("name", String.class); // (3)
property.set(person, "Fred"); // (4)
String name = property.get(person); // (5)
System.out.println("Hello " + person.getName());

def introspection = BeanIntrospection.getIntrospection(Person) // (1)
Person person = introspection.instantiate("John") // (2)
println("Hello $person.name")

BeanProperty<Person, String> property = introspection.getRequiredProperty("name", String) // (3)
property.set(person, "Fred") // (4)
String name = property.get(person) // (5)
println("Hello $person.name")

val introspection = BeanIntrospection.getIntrospection(Person::class.java) // (1)
val person : Person = introspection.instantiate("John") // (2)
print("Hello ${person.name}")

val property : BeanProperty<Person, String> = introspection.getRequiredProperty("name", String::class.java) // (3)
property.set(person, "Fred") // (4)
val name = property.get(person) // (5)
print("Hello ${person.name}")

import io.micronaut.core.annotation.AccessorsStyle;
import io.micronaut.core.annotation.Introspected;

@Introspected
@AccessorsStyle(readPrefixes = "", writePrefixes = "") // (1)
public class Person {

    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String name() { // (2)
        return name;
    }

    public void name(String name) { // (2)
        this.name = name;
    }

    public int age() { // (2)
        return age;
    }

    public void age(int age) { // (2)
        this.age = age;
    }
}

import io.micronaut.core.annotation.AccessorsStyle
import io.micronaut.core.annotation.Introspected

@Introspected
@AccessorsStyle(readPrefixes = "", writePrefixes = "") // (1)
class Person {

    private String name
    private int age

    Person(String name, int age) {
        this.name = name
        this.age = age
    }

    String name() { // (2)
        return name
    }

    void name(String name) { // (2)
        this.name = name
    }

    int age() { // (2)
        return age
    }

    void age(int age) { // (2)
        this.age = age
    }
}

import io.micronaut.core.annotation.AccessorsStyle
import io.micronaut.core.annotation.Introspected

@Introspected
@AccessorsStyle(readPrefixes = [""], writePrefixes = [""]) // (1)
class Person(private var name: String, private var age: Int) {
    fun name(): String { // (2)
        return name
    }

    fun name(name: String) { // (2)
        this.name = name
    }

    fun age(): Int { // (2)
        return age
    }

    fun age(age: Int) { // (2)
        this.age = age
    }
}

        BeanIntrospection<Person> introspection = BeanIntrospection.getIntrospection(Person)
        Person person = introspection.instantiate('John', 42)

        person.name() == 'John'
        person.age() == 42

        val introspection = BeanIntrospection.getIntrospection(Person::class.java)
        val person = introspection.instantiate("John", 42)

        Assertions.assertEquals("John", person.name())
        Assertions.assertEquals(42, person.age())

import io.micronaut.core.annotation.Introspected;

@Introspected(accessKind = Introspected.AccessKind.FIELD)
public class User {
    public final String name; // (1)
    public int age = 18; // (2)

    public User(String name) {
        this.name = name;
    }
}

import io.micronaut.core.annotation.Introspected

@Introspected(accessKind = Introspected.AccessKind.FIELD)
class User {
    public final String name // (1)
    public int age = 18 // (2)

    User(String name) {
        this.name = name
    }
}

@Introspected(accessKind = [Introspected.AccessKind.FIELD])
class User(
    val name: String // (1)
) {
    var age = 18 // (2)
}

import io.micronaut.core.annotation.Creator;
import io.micronaut.core.annotation.Introspected;

import javax.annotation.concurrent.Immutable;

@Introspected
@Immutable
public class Vehicle {

    private final String make;
    private final String model;
    private final int axles;

    public Vehicle(String make, String model) {
        this(make, model, 2);
    }

    @Creator // (1)
    public Vehicle(String make, String model, int axles) {
        this.make = make;
        this.model = model;
        this.axles = axles;
    }

    public String getMake() {
        return make;
    }

    public String getModel() {
        return model;
    }

    public int getAxles() {
        return axles;
    }
}

import io.micronaut.core.annotation.Creator
import io.micronaut.core.annotation.Introspected

import javax.annotation.concurrent.Immutable

@Introspected
@Immutable
class Vehicle {

    final String make
    final String model
    final int axles

    Vehicle(String make, String model) {
        this(make, model, 2)
    }

    @Creator // (1)
    Vehicle(String make, String model, int axles) {
        this.make = make
        this.model = model
        this.axles = axles
    }
}

import io.micronaut.core.annotation.Creator
import io.micronaut.core.annotation.Introspected

import javax.annotation.concurrent.Immutable

@Introspected
@Immutable
class Vehicle @Creator constructor(val make: String, val model: String, val axles: Int) { // (1)

    constructor(make: String, model: String) : this(make, model, 2) {}
}

import io.micronaut.core.annotation.Creator;
import io.micronaut.core.annotation.Introspected;

import javax.annotation.concurrent.Immutable;

@Introspected
@Immutable
public class Business {

    private final String name;

    private Business(String name) {
        this.name = name;
    }

    @Creator // (1)
    public static Business forName(String name) {
        return new Business(name);
    }

    public String getName() {
        return name;
    }
}

import io.micronaut.core.annotation.Creator
import io.micronaut.core.annotation.Introspected

import javax.annotation.concurrent.Immutable

@Introspected
@Immutable
class Business {

    final String name

    private Business(String name) {
        this.name = name
    }

    @Creator // (1)
    static Business forName(String name) {
        new Business(name)
    }
}

import io.micronaut.core.annotation.Creator
import io.micronaut.core.annotation.Introspected

import javax.annotation.concurrent.Immutable

@Introspected
@Immutable
class Business private constructor(val name: String) {
    companion object {

        @Creator // (1)
        fun forName(name: String): Business {
            return Business(name)
        }
    }

}

@Introspected(builder = @Introspected.IntrospectionBuilder(
    builderClass = Person.Builder.class
))
public class Person {
    private final String name;
    private final int age;
    private Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public static Builder builder() {
        return new Builder();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Person person = (Person) o;

        if (age != person.age) return false;
        return Objects.equals(name, person.name);
    }

    @Override
    public int hashCode() {
        int result = name != null ? name.hashCode() : 0;
        result = 31 * result + age;
        return result;
    }

    public static final class Builder {
        private String name;
        private int age;

        public Builder name(String name) {
            this.name = name;
            return this;
        }

        public Builder age(int age) {
            this.age = age;
            return this;
        }

        public Person build() {
            Objects.requireNonNull(name);
            if (age < 1) {
                throw new IllegalArgumentException("Age must be a positive number");
            }
            return new Person(name, age);
        }
    }
}

import io.micronaut.core.annotation.Introspected
@CompileStatic
@Introspected(builder = @Introspected.IntrospectionBuilder(
        builderClass = Person.Builder.class
))
@EqualsAndHashCode
class Person {
    final String name
    final int age

    private Person(String name, int age) {
        this.name = name
        this.age = age
    }

    static Builder builder() {
        new Builder()
    }

    static final class Builder {
        private String name
        private int age

        Builder name(String name) {
            this.name = name
            this
        }

        Builder age(int age) {
            this.age = age
            this
        }

        Person build() {
            Objects.requireNonNull(name)
            if (age < 1) {
                throw new IllegalArgumentException("Age must be a positive number")
            }
            new Person(name, age)
        }
    }
}

@Introspected(builder = Introspected.IntrospectionBuilder(builderClass = Person.Builder::class))
data class Person private constructor(val name: String, val age: Int) {
    data class Builder(
        var name: String? = null,
        var age: Int = 0
    ) {
        fun name(name: String) = apply { this.name = name }
        fun age(age: Int) = apply { this.age = age }

        fun build(): Person {
            requireNotNull(name) { "Name must be specified" }
            require(age >= 1) { "Age must be a positive number" }
            return Person(name!!, age)
        }
    }
}

BeanIntrospection<Person> introspection = BeanIntrospection.getIntrospection(Person.class);
BeanIntrospection.Builder<Person> builder = introspection.builder();
Person person = builder
    .with("age", 25)
    .with("name", "Fred")
    .build();

BeanIntrospection<Person> introspection = BeanIntrospection.getIntrospection(Person.class);
BeanIntrospection.Builder<Person> builder = introspection.builder()
Person person = builder
        .with("age", 25)
        .with("name", "Fred")
        .build()

val introspection = BeanIntrospection.getIntrospection(
    Person::class.java
)
val builder = introspection.builder()
val person = builder
    .with("age", 25)
    .with("name", "Fred")
    .build()

import io.micronaut.core.annotation.Introspected;

@Introspected(classes = Person.class)
public class PersonConfiguration {
}

import io.micronaut.core.annotation.Introspected

@Introspected(classes = Person)
class PersonConfiguration {
}

import io.micronaut.core.annotation.Introspected

@Introspected(classes = [Person::class])
class PersonConfiguration

final BeanWrapper<Person> wrapper = BeanWrapper.getWrapper(new Person("Fred")); // (1)

wrapper.setProperty("age", "20"); // (2)
int newAge = wrapper.getRequiredProperty("age", int.class); // (3)

System.out.println("Person's age now " + newAge);

final BeanWrapper<Person> wrapper = BeanWrapper.getWrapper(new Person("Fred")) // (1)

wrapper.setProperty("age", "20") // (2)
int newAge = wrapper.getRequiredProperty("age", Integer) // (3)

println("Person's age now $newAge")

val wrapper = BeanWrapper.getWrapper(Person("Fred")) // (1)

wrapper.setProperty("age", "20") // (2)
val newAge = wrapper.getRequiredProperty("age", Int::class.java) // (3)

println("Person's age now $newAge")

ApplicationContext applicationContext = ApplicationContext.run("test", "android");
Environment environment = applicationContext.getEnvironment();

assertTrue(environment.getActiveNames().contains("test"));
assertTrue(environment.getActiveNames().contains("android"));

when:
ApplicationContext applicationContext = ApplicationContext.run("test", "android")
Environment environment = applicationContext.getEnvironment()

then:
environment.activeNames.contains("test")
environment.activeNames.contains("android")

val applicationContext = ApplicationContext.run("test", "android")
val environment = applicationContext.environment

environment.activeNames shouldContain "test"
environment.activeNames shouldContain "android"

ApplicationContext applicationContext = ApplicationContext.run(
        PropertySource.of(
                "test",
                CollectionUtils.mapOf(
                    "micronaut.server.host", "foo",
                    "micronaut.server.port", 8080
                )
        ),
        "test", "android");
Environment environment = applicationContext.getEnvironment();

assertEquals("foo", environment.getProperty("micronaut.server.host", String.class).orElse("localhost"));

when:
ApplicationContext applicationContext = ApplicationContext.run(
        PropertySource.of(
                "test",
                [
                    "micronaut.server.host": "foo",
                    "micronaut.server.port": 8080
                ]
        ),
        "test", "android")
Environment environment = applicationContext.getEnvironment()

then:
"foo" == environment.getProperty("micronaut.server.host", String.class).orElse("localhost")

val applicationContext = ApplicationContext.run(
    PropertySource.of(
        "test",
        mapOf(
            "micronaut.server.host" to "foo",
            "micronaut.server.port" to 8080
        )
    ),
    "test", "android"
)
val environment = applicationContext.environment

environment.getProperty("micronaut.server.host", String::class.java).orElse("localhost") shouldBe "foo"

import io.micronaut.context.annotation.ConfigurationProperties;

import jakarta.validation.constraints.Min;
import jakarta.validation.constraints.NotBlank;
import java.util.Optional;

@ConfigurationProperties("my.engine") // (1)
public class EngineConfig {

    public String getManufacturer() {
        return manufacturer;
    }

    public void setManufacturer(String manufacturer) {
        this.manufacturer = manufacturer;
    }

    public int getCylinders() {
        return cylinders;
    }

    public void setCylinders(int cylinders) {
        this.cylinders = cylinders;
    }

    public CrankShaft getCrankShaft() {
        return crankShaft;
    }

    public void setCrankShaft(CrankShaft crankShaft) {
        this.crankShaft = crankShaft;
    }

    @NotBlank // (2)
    private String manufacturer = "Ford"; // (3)

    @Min(1L)
    private int cylinders;

    private CrankShaft crankShaft = new CrankShaft();

    @ConfigurationProperties("crank-shaft")
    public static class CrankShaft { // (4)

        private Optional<Double> rodLength = Optional.empty(); // (5)

        public Optional<Double> getRodLength() {
            return rodLength;
        }

        public void setRodLength(Optional<Double> rodLength) {
            this.rodLength = rodLength;
        }
    }
}

import io.micronaut.context.annotation.ConfigurationProperties

import jakarta.validation.constraints.Min
import jakarta.validation.constraints.NotBlank

@ConfigurationProperties('my.engine') // (1)
class EngineConfig {

    @NotBlank // (2)
    String manufacturer = "Ford" // (3)

    @Min(1L)
    int cylinders

    CrankShaft crankShaft = new CrankShaft()

    @ConfigurationProperties('crank-shaft')
    static class CrankShaft { // (4)
        Optional<Double> rodLength = Optional.empty() // (5)
    }
}

import io.micronaut.context.annotation.ConfigurationProperties
import java.util.Optional
import jakarta.validation.constraints.Min
import jakarta.validation.constraints.NotBlank

@ConfigurationProperties("my.engine") // (1)
class EngineConfig {

    @NotBlank // (2)
    var manufacturer = "Ford" // (3)

    @Min(1L)
    var cylinders: Int = 0

    var crankShaft = CrankShaft()

    @ConfigurationProperties("crank-shaft")
    class CrankShaft { // (4)
        var rodLength: Optional<Double> = Optional.empty() // (5)
    }
}

@Singleton
public class EngineImpl implements Engine {
    private final EngineConfig config;

    public EngineImpl(EngineConfig config) { // (1)
        this.config = config;
    }

    @Override
    public int getCylinders() {
        return config.getCylinders();
    }

    @Override
    public String start() {// (2)
        return getConfig().getManufacturer() + " Engine Starting V" + getConfig().getCylinders() +
                " [rodLength=" + getConfig().getCrankShaft().getRodLength().orElse(6d) + "]";
    }

    public final EngineConfig getConfig() {
        return config;
    }
}

@Singleton
class EngineImpl implements Engine {
    final EngineConfig config

    EngineImpl(EngineConfig config) { // (1)
        this.config = config
    }

    @Override
    int getCylinders() {
        config.cylinders
    }

    @Override
    String start() { // (2)
        "$config.manufacturer Engine Starting V$config.cylinders [rodLength=${config.crankShaft.rodLength.orElse(6.0d)}]"
    }
}

@Singleton
class EngineImpl(val config: EngineConfig) : Engine {// (1)

    override val cylinders: Int
        get() = config.cylinders

    override fun start(): String {// (2)
        return "${config.manufacturer} Engine Starting V${config.cylinders} [rodLength=${config.crankShaft.rodLength.orElse(6.0)}]"
    }
}

Map<String, Object> map = new LinkedHashMap<>(1);
map.put("my.engine.cylinders", "8");
ApplicationContext applicationContext = ApplicationContext.run(map, "test");

Vehicle vehicle = applicationContext.getBean(Vehicle.class);
System.out.println(vehicle.start());

ApplicationContext applicationContext = ApplicationContext.run(
        ['my.engine.cylinders': '8'],
        "test"
)

def vehicle = applicationContext.getBean(Vehicle)
println(vehicle.start())

val map = mapOf( "my.engine.cylinders" to "8")
val applicationContext = ApplicationContext.run(map, "test")

val vehicle = applicationContext.getBean(Vehicle::class.java)
println(vehicle.start())