@ -675,7 +675,7 @@ The preceding POJO defines the following properties:
* `my.service.security.password`.
* `my.service.security.password`.
* `my.service.security.roles`, with a collection of `String` that defaults to `USER`.
* `my.service.security.roles`, with a collection of `String` that defaults to `USER`.
NOTE: The properties that map to `@ConfigurationProperties` classes available in Spring Boot, which are configured via properties files, YAML files, environment variables, etc., are public API but the accessors (getters/setters) of the class itself are not meant to be used directly.
NOTE: The properties that map to `@ConfigurationProperties` classes available in Spring Boot, which are configured through properties files, YAML files, environment variables etc., are public API but the accessors (getters/setters) of the class itself are not meant to be used directly.
[NOTE]
[NOTE]
====
====
@ -712,7 +712,7 @@ This means that the binder will expect to find a constructor with the parameters
If you are using Java 16 or later, constructor binding can be used with records.
If you are using Java 16 or later, constructor binding can be used with records.
In this case, unless your record has multiple constructors, there is no need to use `@ConstructorBinding`.
In this case, unless your record has multiple constructors, there is no need to use `@ConstructorBinding`.
Nested members of a `@ConstructorBinding` class (such as `Security` in the example above) will also be bound via their constructor.
Nested members of a `@ConstructorBinding` class (such as `Security` in the example above) will also be bound through their constructor.
Default values can be specified using `@DefaultValue` and the same conversion service will be applied to coerce the `String` value to the target type of a missing property.
Default values can be specified using `@DefaultValue` and the same conversion service will be applied to coerce the `String` value to the target type of a missing property.
By default, if no properties are bound to `Security`, the `MyProperties` instance will contain a `null` value for `security`.
By default, if no properties are bound to `Security`, the `MyProperties` instance will contain a `null` value for `security`.
NOTE: To use constructor binding the class must be enabled using `@EnableConfigurationProperties` or configuration property scanning.
NOTE: To use constructor binding the class must be enabled using `@EnableConfigurationProperties` or configuration property scanning.
You cannot use constructor binding with beans that are created by the regular Spring mechanisms (for example `@Component` beans, beans created via `@Bean` methods or beans loaded using `@Import`)
You cannot use constructor binding with beans that are created by the regular Spring mechanisms (e.g. `@Component` beans, beans created by using `@Bean` methods or beans loaded by using `@Import`)
TIP: If you have more than one constructor for your class you can also use `@ConstructorBinding` directly on the constructor that should be bound.
TIP: If you have more than one constructor for your class you can also use `@ConstructorBinding` directly on the constructor that should be bound.
When the `@ConfigurationProperties` bean is registered using configuration property scanning or via `@EnableConfigurationProperties`, the bean has a conventional name: `<prefix>-<fqn>`, where `<prefix>` is the environment key prefix specified in the `@ConfigurationProperties` annotation and `<fqn>` is the fully qualified name of the bean.
When the `@ConfigurationProperties` bean is registered using configuration property scanning or through `@EnableConfigurationProperties`, the bean has a conventional name: `<prefix>-<fqn>`, where `<prefix>` is the environment key prefix specified in the `@ConfigurationProperties` annotation and `<fqn>` is the fully qualified name of the bean.
If the annotation does not provide any prefix, only the fully qualified name of the bean is used.
If the annotation does not provide any prefix, only the fully qualified name of the bean is used.
The bean name in the example above is `com.example.app-com.example.app.SomeProperties`.
The bean name in the example above is `com.example.app-com.example.app.SomeProperties`.
@ -1215,4 +1215,4 @@ Doing so will provide you with structured, type-safe object that you can inject
`SpEL` expressions from <<features#features.external-config.files,application property files>> are not processed at time of parsing these files and populating the environment.
`SpEL` expressions from <<features#features.external-config.files,application property files>> are not processed at time of parsing these files and populating the environment.
However, it is possible to write a `SpEL` expression in `@Value`.
However, it is possible to write a `SpEL` expression in `@Value`.
If the value of a property from an application property file is a `SpEL` expression, it will be evaluated when consumed via `@Value`.
If the value of a property from an application property file is a `SpEL` expression, it will be evaluated when consumed through `@Value`.
@ -6,14 +6,14 @@ Spring Boot provides Kotlin support by leveraging the support in other Spring pr
See the {spring-framework-docs}/languages.html#kotlin[Spring Framework Kotlin support documentation] for more information.
See the {spring-framework-docs}/languages.html#kotlin[Spring Framework Kotlin support documentation] for more information.
The easiest way to start with Spring Boot and Kotlin is to follow https://spring.io/guides/tutorials/spring-boot-kotlin/[this comprehensive tutorial].
The easiest way to start with Spring Boot and Kotlin is to follow https://spring.io/guides/tutorials/spring-boot-kotlin/[this comprehensive tutorial].
You can create new Kotlin projects via https://start.spring.io/#!language=kotlin[start.spring.io].
You can create new Kotlin projects by using https://start.spring.io/#!language=kotlin[start.spring.io].
Feel free to join the #spring channel of https://slack.kotlinlang.org/[Kotlin Slack] or ask a question with the `spring` and `kotlin` tags on https://stackoverflow.com/questions/tagged/spring+kotlin[Stack Overflow] if you need support.
Feel free to join the #spring channel of https://slack.kotlinlang.org/[Kotlin Slack] or ask a question with the `spring` and `kotlin` tags on https://stackoverflow.com/questions/tagged/spring+kotlin[Stack Overflow] if you need support.
[[features.kotlin.requirements]]
[[features.kotlin.requirements]]
=== Requirements
=== Requirements
Spring Boot requires at least Kotlin 1.3.x and manages a suitable Kotlin version via dependency management.
Spring Boot requires at least Kotlin 1.3.x and manages a suitable Kotlin version through dependency management.
To use Kotlin, `org.jetbrains.kotlin:kotlin-stdlib` and `org.jetbrains.kotlin:kotlin-reflect` must be present on the classpath.
To use Kotlin, `org.jetbrains.kotlin:kotlin-stdlib` and `org.jetbrains.kotlin:kotlin-reflect` must be present on the classpath.
The `kotlin-stdlib` variants `kotlin-stdlib-jdk7` and `kotlin-stdlib-jdk8` can also be used.
The `kotlin-stdlib` variants `kotlin-stdlib-jdk7` and `kotlin-stdlib-jdk8` can also be used.
@ -34,7 +34,7 @@ It deals with `null` values at compile time rather than deferring the problem to
This helps to eliminate a common source of bugs without paying the cost of wrappers like `Optional`.
This helps to eliminate a common source of bugs without paying the cost of wrappers like `Optional`.
Kotlin also allows using functional constructs with nullable values as described in this https://www.baeldung.com/kotlin-null-safety[comprehensive guide to null-safety in Kotlin].
Kotlin also allows using functional constructs with nullable values as described in this https://www.baeldung.com/kotlin-null-safety[comprehensive guide to null-safety in Kotlin].
Although Java does not allow one to express null-safety in its type system, Spring Framework, Spring Data, and Reactor now provide null-safety of their API via tooling-friendly annotations.
Although Java does not allow one to express null-safety in its type system, Spring Framework, Spring Data, and Reactor now provide null-safety of their API through tooling-friendly annotations.
By default, types from Java APIs used in Kotlin are recognized as {kotlin-docs}java-interop.html#null-safety-and-platform-types[platform types] for which null-checks are relaxed.
By default, types from Java APIs used in Kotlin are recognized as {kotlin-docs}java-interop.html#null-safety-and-platform-types[platform types] for which null-checks are relaxed.
{kotlin-docs}java-interop.html#jsr-305-support[Kotlin's support for JSR 305 annotations] combined with nullability annotations provide null-safety for the related Spring API in Kotlin.
{kotlin-docs}java-interop.html#jsr-305-support[Kotlin's support for JSR 305 annotations] combined with nullability annotations provide null-safety for the related Spring API in Kotlin.
@ -96,11 +96,11 @@ Among other things, the extensions make it possible to take advantage of Kotlin
=== Dependency management
=== Dependency management
In order to avoid mixing different versions of Kotlin dependencies on the classpath, Spring Boot imports the Kotlin BOM.
In order to avoid mixing different versions of Kotlin dependencies on the classpath, Spring Boot imports the Kotlin BOM.
With Maven, the Kotlin version can be customized via the `kotlin.version` property and plugin management is provided for `kotlin-maven-plugin`.
With Maven, the Kotlin version can be customized by setting the `kotlin.version` property and plugin management is provided for `kotlin-maven-plugin`.
With Gradle, the Spring Boot plugin automatically aligns the `kotlin.version` with the version of the Kotlin plugin.
With Gradle, the Spring Boot plugin automatically aligns the `kotlin.version` with the version of the Kotlin plugin.
Spring Boot also manages the version of Coroutines dependencies by importing the Kotlin Coroutines BOM.
Spring Boot also manages the version of Coroutines dependencies by importing the Kotlin Coroutines BOM.
The version can be customized via the `kotlin-coroutines.version` property.
The version can be customized by setting the `kotlin-coroutines.version` property.
TIP: `org.jetbrains.kotlinx:kotlinx-coroutines-reactor` dependency is provided by default if one bootstraps a Kotlin project with at least one reactive dependency on https://start.spring.io/#!language=kotlin[start.spring.io].
TIP: `org.jetbrains.kotlinx:kotlinx-coroutines-reactor` dependency is provided by default if one bootstraps a Kotlin project with at least one reactive dependency on https://start.spring.io/#!language=kotlin[start.spring.io].
@ -11,7 +11,7 @@ TIP: There are a lot of logging frameworks available for Java.
Do not worry if the above list seems confusing.
Do not worry if the above list seems confusing.
Generally, you do not need to change your logging dependencies and the Spring Boot defaults work just fine.
Generally, you do not need to change your logging dependencies and the Spring Boot defaults work just fine.
TIP: When you deploy your application to a servlet container or application server, logging performed via the Java Util Logging API is not routed into your application's logs.
TIP: When you deploy your application to a servlet container or application server, logging performed with the Java Util Logging API is not routed into your application's logs.
This prevents logging performed by the container or other applications that have been deployed to it from appearing in your application's logs.
This prevents logging performed by the container or other applications that have been deployed to it from appearing in your application's logs.
@ -288,7 +288,7 @@ The value should be the fully qualified class name of a `LoggingSystem` implemen
You can also disable Spring Boot's logging configuration entirely by using a value of `none`.
You can also disable Spring Boot's logging configuration entirely by using a value of `none`.
NOTE: Since logging is initialized *before* the `ApplicationContext` is created, it is not possible to control logging from `@PropertySources` in Spring `@Configuration` files.
NOTE: Since logging is initialized *before* the `ApplicationContext` is created, it is not possible to control logging from `@PropertySources` in Spring `@Configuration` files.
The only way to change the logging system or disable it entirely is via System properties.
The only way to change the logging system or disable it entirely is through System properties.
Depending on your logging system, the following files are loaded:
Depending on your logging system, the following files are loaded:
NOTE: If `@ConfigurationProperties` beans are registered via `@EnableConfigurationProperties` instead of automatic scanning, the `@Profile` annotation needs to be specified on the `@Configuration` class that has the `@EnableConfigurationProperties` annotation.
NOTE: If `@ConfigurationProperties` beans are registered through `@EnableConfigurationProperties` instead of automatic scanning, the `@Profile` annotation needs to be specified on the `@Configuration` class that has the `@EnableConfigurationProperties` annotation.
In the case where `@ConfigurationProperties` are scanned, `@Profile` can be specified on the `@ConfigurationProperties` class itself.
In the case where `@ConfigurationProperties` are scanned, `@Profile` can be specified on the `@ConfigurationProperties` class itself.
You can use a configprop:spring.profiles.active[] `Environment` property to specify which profiles are active.
You can use a configprop:spring.profiles.active[] `Environment` property to specify which profiles are active.
TIP: This setup is only supported by WebFlux applications as using `WebTestClient` in a mocked web application only works with WebFlux at the moment.
TIP: This setup is only supported by WebFlux applications as using `WebTestClient` in a mocked web application only works with WebFlux at the moment.
NOTE: `@WebFluxTest` cannot detect routes registered via the functional web framework.
NOTE: `@WebFluxTest` cannot detect routes registered through the functional web framework.
For testing `RouterFunction` beans in the context, consider importing your `RouterFunction` yourself via `@Import` or using `@SpringBootTest`.
For testing `RouterFunction` beans in the context, consider importing your `RouterFunction` yourself by using `@Import` or by using `@SpringBootTest`.
NOTE: `@WebFluxTest` cannot detect custom security configuration registered via a `@Bean` of type `SecurityWebFilterChain`.
NOTE: `@WebFluxTest` cannot detect custom security configuration registered as a `@Bean` of type `SecurityWebFilterChain`.
To include that in your test, you will need to import the configuration that registers the bean via `@Import` or use `@SpringBootTest`.
To include that in your test, you will need to import the configuration that registers the bean by using `@Import` or by using `@SpringBootTest`.
TIP: Sometimes writing Spring WebFlux tests is not enough; Spring Boot can help you run <<features#features.testing.spring-boot-applications.with-running-server, full end-to-end tests with an actual server>>.
TIP: Sometimes writing Spring WebFlux tests is not enough; Spring Boot can help you run <<features#features.testing.spring-boot-applications.with-running-server, full end-to-end tests with an actual server>>.
You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password).
You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password).
In either case, the template is fault tolerant.
In either case, the template is fault tolerant.
This means that it behaves in a test-friendly way by not throwing exceptions on 4xx and 5xx errors.
This means that it behaves in a test-friendly way by not throwing exceptions on 4xx and 5xx errors.
Instead, such errors can be detected via the returned `ResponseEntity` and its status code.
Instead, such errors can be detected through the returned `ResponseEntity` and its status code.
TIP: Spring Framework 5.0 provides a new `WebTestClient` that works for <<features#features.testing.spring-boot-applications.spring-webflux-tests, WebFlux integration tests>> and both <<features#features.testing.spring-boot-applications.with-running-server, WebFlux and MVC end-to-end testing>>.
TIP: Spring Framework 5.0 provides a new `WebTestClient` that works for <<features#features.testing.spring-boot-applications.spring-webflux-tests, WebFlux integration tests>> and both <<features#features.testing.spring-boot-applications.with-running-server, WebFlux and MVC end-to-end testing>>.
It provides a fluent API for assertions, unlike `TestRestTemplate`.
It provides a fluent API for assertions, unlike `TestRestTemplate`.
Embedded Tomcat's MBean registry is disabled by default.
Embedded Tomcat's MBean registry is disabled by default.
This minimizes Tomcat's memory footprint.
This minimizes Tomcat's memory footprint.
If you want to use Tomcat's MBeans, for example so that they can be used to expose metrics via Micrometer, you must use the configprop:server.tomcat.mbeanregistry.enabled[] property to do so, as shown in the following example:
If you want to use Tomcat's MBeans, for example so that they can be used by Micrometer to expose metrics, you must use the configprop:server.tomcat.mbeanregistry.enabled[] property to do so, as shown in the following example:
@ -44,7 +44,7 @@ To enable overwriting existing job definitions set the configprop:spring.quartz.
Quartz Scheduler configuration can be customized using `spring.quartz` properties and `SchedulerFactoryBeanCustomizer` beans, which allow programmatic `SchedulerFactoryBean` customization.
Quartz Scheduler configuration can be customized using `spring.quartz` properties and `SchedulerFactoryBeanCustomizer` beans, which allow programmatic `SchedulerFactoryBean` customization.
Advanced Quartz configuration properties can be customized using `spring.quartz.properties.*`.
Advanced Quartz configuration properties can be customized using `spring.quartz.properties.*`.
NOTE: In particular, an `Executor` bean is not associated with the scheduler as Quartz offers a way to configure the scheduler via `spring.quartz.properties`.
NOTE: In particular, an `Executor` bean is not associated with the scheduler as Quartz offers a way to configure the scheduler through `spring.quartz.properties`.
If you need to customize the task executor, consider implementing `SchedulerFactoryBeanCustomizer`.
If you need to customize the task executor, consider implementing `SchedulerFactoryBeanCustomizer`.
Jobs can define setters to inject data map properties.
Jobs can define setters to inject data map properties.
@ -60,7 +60,7 @@ TIP: A custom `ChainedKafkaTransactionManager` must be marked `@Primary` as it u
[[messaging.kafka.streams]]
[[messaging.kafka.streams]]
=== Kafka Streams
=== Kafka Streams
Spring for Apache Kafka provides a factory bean to create a `StreamsBuilder` object and manage the lifecycle of its streams.
Spring for Apache Kafka provides a factory bean to create a `StreamsBuilder` object and manage the lifecycle of its streams.
Spring Boot auto-configures the required `KafkaStreamsConfiguration` bean as long as `kafka-streams` is on the classpath and Kafka Streams is enabled via the `@EnableKafkaStreams` annotation.
Spring Boot auto-configures the required `KafkaStreamsConfiguration` bean as long as `kafka-streams` is on the classpath and Kafka Streams is enabled by the `@EnableKafkaStreams` annotation.
Enabling Kafka Streams means that the application id and bootstrap servers must be set.
Enabling Kafka Streams means that the application id and bootstrap servers must be set.
The former can be configured using `spring.kafka.streams.application-id`, defaulting to `spring.application.name` if not set.
The former can be configured using `spring.kafka.streams.application-id`, defaulting to `spring.application.name` if not set.
https://rsocket.io[RSocket] is a binary protocol for use on byte stream transports.
https://rsocket.io[RSocket] is a binary protocol for use on byte stream transports.
It enables symmetric interaction models via async message passing over a single connection.
It enables symmetric interaction models through async message passing over a single connection.
The `spring-messaging` module of the Spring Framework provides support for RSocket requesters and responders, both on the client and on the server side.
The `spring-messaging` module of the Spring Framework provides support for RSocket requesters and responders, both on the client and on the server side.
Andy Wilkinson
3 years ago