It is easily possible to package a Spring Boot fat jar as a docker image.
However, there are various downsides to copying and running the fat jar as is in the docker image.
There’s always a certain amount of overhead when running a fat jar without unpacking it, and in a containerized environment this can be noticeable.
@ -9,7 +9,7 @@ If you put jar files in the layer before your application classes, Docker often
[[container-images.efficient-images.unpacking]]
=== Unpacking the fat jar
=== Unpacking the Executable JAR
If you are running your application from a container, you can use an executable jar, but it is also often an advantage to explode it and run it in a different way.
Certain PaaS implementations may also choose to unpack archives before they run.
==== Connecting to Elasticsearch using REST clients
==== Connecting to Elasticsearch Using REST clients
Elasticsearch ships two different REST clients] that you can use to query a cluster: the https://www.elastic.co/guide/en/elasticsearch/client/java-api-client/current/java-rest-low.html[low-level client] from the `org.elasticsearch.client:elasticsearch-rest-client` module and the https://www.elastic.co/guide/en/elasticsearch/client/java-api-client/current/index.html[Java API client] from the `co.elastic.clients:elasticsearch-java` module.
Additionally, Spring Boot provides support for a reactive client from the `org.springframework.data:spring-data-elasticsearch` module.
By default, the clients will target `http://localhost:9200`.
@ -237,7 +237,7 @@ You can use `spring.elasticsearch.*` properties to further tune how the clients
===== Connecting to Elasticsearch using RestClient
===== Connecting to Elasticsearch Using RestClient
If you have `elasticsearch-rest-client` on the classpath, Spring Boot will auto-configure and register a `RestClient` bean.
In addition to the properties described previously, to fine-tune the `RestClient` you can register an arbitrary number of beans that implement `RestClientBuilderCustomizer` for more advanced customizations.
To take full control over the clients' configuration, define a `RestClientBuilder` bean.
@ -259,7 +259,7 @@ You can further tune how `Sniffer` is configured, as shown in the following exam
=== Compatibility with the Standard Java "`JarFile`"
=== Compatibility With the Standard Java "`JarFile`"
Spring Boot Loader strives to remain compatible with existing code and libraries.
`org.springframework.boot.loader.jar.JarFile` extends from `java.util.jar.JarFile` and should work as a drop-in replacement.
The `getURL()` method returns a `URL` that opens a connection compatible with `java.net.JarURLConnection` and can be used with Java's `URLClassLoader`.
Spring Boot will automatically find and load `application.properties` and `application.yaml` files from the following locations when your application starts:
. From the classpath
@ -471,7 +471,7 @@ See the _<<howto#howto.properties-and-configuration.short-command-line-arguments
[[features.external-config.files.multi-document]]
==== Working with Multi-Document Files
==== Working With Multi-Document Files
Spring Boot allows you to split a single physical file into multiple logical documents which are each added independently.
Documents are processed in order, from top to bottom.
Later documents can override the properties defined in earlier ones.
@ -564,7 +564,7 @@ If you need a secure way to store credentials and passwords, the https://cloud.s
[[features.external-config.yaml]]
=== Working with YAML
=== Working With YAML
https://yaml.org[YAML] is a superset of JSON and, as such, is a convenient format for specifying hierarchical configuration data.
The `SpringApplication` class automatically supports YAML as an alternative to properties whenever you have the https://github.com/snakeyaml/snakeyaml[SnakeYAML] library on your classpath.
@ -677,7 +677,7 @@ TIP: See also the <<features#features.external-config.typesafe-configuration-pro
Spring Boot provides infrastructure to bind `@ConfigurationProperties` types and register them as beans.
You can either enable configuration properties on a class-by-class basis or enable configuration property scanning that works in a similar manner to component scanning.
@ -779,7 +779,7 @@ If you still want to inject other beans using the constructor, the configuration
https://kotlinlang.org[Kotlin] is a statically-typed language targeting the JVM (and other platforms) which allows writing concise and elegant code while providing {kotlin-docs}java-interop.html[interoperability] with existing libraries written in Java.
Spring Boot provides Kotlin support by leveraging the support in other Spring projects such as Spring Framework, Spring Data, and Reactor.
By default, `@SpringBootTest` does not start the server but instead sets up a mock environment for testing web endpoints.
With Spring MVC, we can query our web endpoints using {spring-framework-docs}/testing.html#spring-mvc-test-framework[`MockMvc`] or `WebTestClient`, as shown in the following example:
@ -218,7 +218,7 @@ If you need to test these lower-level concerns, you can start a fully running se
===== Auto-configured Spring REST Docs Tests with Mock MVC
===== Auto-configured Spring REST Docs Tests With Mock MVC
`@AutoConfigureRestDocs` customizes the `MockMvc` bean to use Spring REST Docs when testing servlet-based web applications.
You can inject it by using `@Autowired` and use it in your tests as you normally would when using Mock MVC and Spring REST Docs, as shown in the following example:
===== Auto-configured Spring REST Docs Tests with WebTestClient
===== Auto-configured Spring REST Docs Tests With WebTestClient
`@AutoConfigureRestDocs` can also be used with `WebTestClient` when testing reactive web applications.
You can inject it by using `@Autowired` and use it in your tests as you normally would when using `@WebFluxTest` and Spring REST Docs, as shown in the following example:
===== Auto-configured Spring REST Docs Tests with REST Assured
===== Auto-configured Spring REST Docs Tests With REST Assured
`@AutoConfigureRestDocs` makes a `RequestSpecification` bean, preconfigured to use Spring REST Docs, available to your tests.
You can inject it by using `@Autowired` and use it in your tests as you normally would when using REST Assured and Spring REST Docs, as shown in the following example:
@ -32,7 +32,7 @@ See {spring-boot-autoconfigure-module-code}/batch/BatchAutoConfiguration.java[Ba
[[howto.batch.running-from-the-command-line]]
=== Running from the Command Line
=== Running From the Command Line
Spring Boot converts any command line argument starting with `--` to a property to add to the `Environment`, see <<features#features.external-config.command-line-args,accessing command line properties>>.
This should not be used to pass arguments to batch jobs.
To specify batch arguments on the command line, use the regular format (that is without `--`), as shown in the following example:
If you are upgrading from the `1.x` release of Spring Boot, check the {github-wiki}/Spring-Boot-2.0-Migration-Guide["`migration guide`" on the project wiki] that provides detailed upgrade instructions.
Check also the {github-wiki}["`release notes`"] for a list of "`new and noteworthy`" features for each release.
When upgrading to a new feature release, some properties may have been renamed or removed.
Spring Boot provides a way to analyze your application's environment and print diagnostics at startup, but also temporarily migrate properties at runtime for you.
By default, each time your application restarts, a report showing the condition evaluation delta is logged.
The report shows the changes to your application's auto-configuration as you make changes such as adding or removing beans and setting configuration properties.
When deployed to a servlet container, Spring Boot uses its error page filter to forward a request with an error status to the appropriate error page.
This is necessary as the servlet specification does not provide an API for registering error pages.
Depending on the container that you are deploying your war file to and the technologies that your application uses, some additional configuration may be required.
@ -465,7 +465,7 @@ By default, the embedded server listens for HTTP requests on port `8080`.
When using an embedded servlet container, you can register servlets, filters, and all the listeners (such as `HttpSessionListener`) from the servlet spec, either by using Spring beans or by scanning for servlet components.
@ -147,7 +147,7 @@ For production environments, consider using a `JdbcOAuth2AuthorizedClientService
[[web.security.oauth2.client.common-providers]]
===== OAuth2 client registration for common providers
===== OAuth2 Client Registration for Common Providers
For common OAuth2 and OpenID providers, including Google, Github, Facebook, and Okta, we provide a set of provider defaults (`google`, `github`, `facebook`, and `okta`, respectively).
If you do not need to customize these providers, you can set the `provider` attribute to the one for which you need to infer defaults.
Phillip Webb
2 years ago