[[getting-started]]
= Getting Started

[partintro]
--
If you are getting started with Spring Boot, or "`Spring`" in general, start by reading
this section. It answers the basic "`what?`", "`how?`" and "`why?`" questions. It
includes an introduction to Spring Boot, along with installation instructions. We then
walk you through building your first Spring Boot application, discussing some core
principles as we go.
--



[[getting-started-introducing-spring-boot]]
== Introducing Spring Boot
Spring Boot makes it easy to create stand-alone, production-grade Spring-based
Applications that you can run. We take an opinionated view of the Spring platform and
third-party libraries, so that you can get started with minimum fuss. Most Spring Boot
applications need very little Spring configuration.

You can use Spring Boot to create Java applications that can be started by using
`java -jar` or more traditional war deployments. We also provide a command line tool that
runs "`spring scripts`".

Our primary goals are:

* Provide a radically faster and widely accessible getting-started experience for all
Spring development.
* Be opinionated out of the box but get out of the way quickly as requirements start to
diverge from the defaults.
* Provide a range of non-functional features that are common to large classes of projects
(such as embedded servers, security, metrics, health checks, and externalized
configuration).
* Absolutely no code generation and no requirement for XML configuration.



[[getting-started-system-requirements]]
== System Requirements
Spring Boot {spring-boot-version} requires https://www.java.com[Java 8 or 9] and
{spring-reference}[Spring Framework {spring-version}] or above.

Explicit build support is provided for the following build tools:

|===
|Build Tool |Version

|Maven
|3.2+

|Gradle
|4.x
|===



[[getting-started-system-requirements-servlet-containers]]
=== Servlet Containers
Spring Boot supports the following embedded servlet containers:

|===
|Name |Servlet Version

|Tomcat 8.5
|3.1

|Jetty 9.4
|3.1

|Undertow 1.4
|3.1
|===

You can also deploy Spring Boot applications to any Servlet 3.1+ compatible container.



[[getting-started-installing-spring-boot]]
== Installing Spring Boot
Spring Boot can be used with "`classic`" Java development tools or installed as a command
line tool. Either way, you need https://www.java.com[Java SDK v1.8] or higher. Before you
begin, you should check your current Java installation by using the following command:

[indent=0]
----
	$ java -version
----

If you are new to Java development or if you want to experiment with Spring Boot, you
might want to try the <<getting-started-installing-the-cli, Spring Boot CLI>> (Command
Line Interface) first. Otherwise, read on for "`classic`" installation instructions.



[[getting-started-installation-instructions-for-java]]
=== Installation Instructions for the Java Developer
You can use Spring Boot in the same way as any standard Java library. To do so, include
the appropriate `+spring-boot-*.jar+` files on your classpath. Spring Boot does not
require any special tools integration, so you can use any IDE or text editor. Also, there
is nothing special about a Spring Boot application, so you can run and debug a Spring
Boot application as you would any other Java program.

Although you _could_ copy Spring Boot jars, we generally recommend that you use a build
tool that supports dependency management (such as Maven or Gradle).



[[getting-started-maven-installation]]
==== Maven Installation
Spring Boot is compatible with Apache Maven 3.2 or above. If you do not already have
Maven installed, you can follow the instructions at https://maven.apache.org.

TIP: On many operating systems, Maven can be installed with a package manager. If you use
OSX Homebrew, try `brew install maven`. Ubuntu users can run
`sudo apt-get install maven`. Windows users with https://chocolatey.org/[Chocolatey] can
run `choco install maven` from an elevated (administrator) prompt.

Spring Boot dependencies use the `org.springframework.boot` `groupId`. Typically, your
Maven POM file inherits from the `spring-boot-starter-parent` project and declares
dependencies to one or more <<using-spring-boot.adoc#using-boot-starter,"`Starters`">>.
Spring Boot also provides an optional
<<build-tool-plugins.adoc#build-tool-plugins-maven-plugin, Maven plugin>> to create
executable jars.

The following listing shows a typical `pom.xml` file:

[source,xml,indent=0,subs="verbatim,quotes,attributes"]
----
	<?xml version="1.0" encoding="UTF-8"?>
	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
		<modelVersion>4.0.0</modelVersion>

		<groupId>com.example</groupId>
		<artifactId>myproject</artifactId>
		<version>0.0.1-SNAPSHOT</version>

		<!-- Inherit defaults from Spring Boot -->
		<parent>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-parent</artifactId>
			<version>{spring-boot-version}</version>
		</parent>

		<!-- Add typical dependencies for a web application -->
		<dependencies>
			<dependency>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-starter-web</artifactId>
			</dependency>
		</dependencies>

		<!-- Package as an executable jar -->
		<build>
			<plugins>
				<plugin>
					<groupId>org.springframework.boot</groupId>
					<artifactId>spring-boot-maven-plugin</artifactId>
				</plugin>
			</plugins>
		</build>

ifeval::["{spring-boot-repo}" != "release"]
		<!-- Add Spring repositories -->
		<!-- (you don't need this if you are using a .RELEASE version) -->
		<repositories>
			<repository>
				<id>spring-snapshots</id>
				<url>https://repo.spring.io/snapshot</url>
				<snapshots><enabled>true</enabled></snapshots>
			</repository>
			<repository>
				<id>spring-milestones</id>
				<url>https://repo.spring.io/milestone</url>
			</repository>
		</repositories>
		<pluginRepositories>
			<pluginRepository>
				<id>spring-snapshots</id>
				<url>https://repo.spring.io/snapshot</url>
			</pluginRepository>
			<pluginRepository>
				<id>spring-milestones</id>
				<url>https://repo.spring.io/milestone</url>
			</pluginRepository>
		</pluginRepositories>
endif::[]
	</project>
----

TIP: The `spring-boot-starter-parent` is a great way to use Spring Boot, but it might not
be suitable all of the time. Sometimes you may need to inherit from a different parent
POM, or you might not like our default settings. In those cases, see
<<using-boot-maven-without-a-parent>> for an alternative solution that uses an `import`
scope.



[[getting-started-gradle-installation]]
==== Gradle Installation
Spring Boot is compatible with Gradle 4. If you do not already have Gradle installed, you
can follow the instructions at https://gradle.org.

Spring Boot dependencies can be declared by using the `org.springframework.boot` `group`.
Typically, your project declares dependencies to one or more
<<using-spring-boot.adoc#using-boot-starter, "`Starters`">>. Spring Boot
provides a useful <<build-tool-plugins.adoc#build-tool-plugins-gradle-plugin, Gradle
plugin>> that can be used to simplify dependency declarations and to create executable
jars.

.Gradle Wrapper
****
The Gradle Wrapper provides a nice way of "`obtaining`" Gradle when you need to build a
project. It is a small script and library that you commit alongside your code to
bootstrap the build process. See {gradle-user-guide}/gradle_wrapper.html for details.
****

The following example shows a typical `build.gradle` file:

[source,groovy,indent=0,subs="verbatim,attributes"]
----
ifeval::["{spring-boot-repo}" == "release"]
	plugins {
		id 'org.springframework.boot' version '{spring-boot-version}'
		id 'java'
	}
endif::[]
ifeval::["{spring-boot-repo}" != "release"]
	buildscript {
		repositories {
			jcenter()
			maven { url 'https://repo.spring.io/snapshot' }
			maven { url 'https://repo.spring.io/milestone' }
		}
		dependencies {
			classpath 'org.springframework.boot:spring-boot-gradle-plugin:{spring-boot-version}'
		}
	}

	apply plugin: 'java'
	apply plugin: 'org.springframework.boot'
	apply plugin: 'io.spring.dependency-management'

endif::[]
	jar {
		baseName = 'myproject'
		version =  '0.0.1-SNAPSHOT'
	}

	repositories {
		jcenter()
ifeval::["{spring-boot-repo}" != "release"]
		maven { url "https://repo.spring.io/snapshot" }
		maven { url "https://repo.spring.io/milestone" }
endif::[]
	}

	dependencies {
		compile("org.springframework.boot:spring-boot-starter-web")
		testCompile("org.springframework.boot:spring-boot-starter-test")
	}
----



[[getting-started-installing-the-cli]]
=== Installing the Spring Boot CLI
The Spring Boot CLI (Command Line Interface) is a command line tool that you can use to
quickly prototype with Spring. It lets you run http://groovy-lang.org/[Groovy] scripts,
which means that you have a familiar Java-like syntax without so much boilerplate code.

You do not need to use the CLI to work with Spring Boot, but it is definitely the
quickest way to get a Spring application off the ground.



[[getting-started-manual-cli-installation]]
==== Manual Installation
You can download the Spring CLI distribution from the Spring software repository:

* https://repo.spring.io/{spring-boot-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.zip[spring-boot-cli-{spring-boot-version}-bin.zip]
* https://repo.spring.io/{spring-boot-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.tar.gz[spring-boot-cli-{spring-boot-version}-bin.tar.gz]

Cutting edge
https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-cli/[snapshot
distributions] are also available.

Once downloaded, follow the
{github-raw}/spring-boot-project/spring-boot-cli/src/main/content/INSTALL.txt[INSTALL.txt]
instructions from the unpacked archive. In summary, there is a `spring` script
(`spring.bat` for Windows) in a `bin/` directory in the `.zip` file. Alternatively, you
can use `java -jar` with the `.jar` file (the script helps you to be sure that the
classpath is set correctly).



[[getting-started-sdkman-cli-installation]]
==== Installation with SDKMAN!
SDKMAN! (The Software Development Kit Manager) can be used for managing multiple versions
of various binary SDKs, including Groovy and the Spring Boot CLI.
Get SDKMAN! from http://sdkman.io and install Spring Boot by using the following
commands:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ sdk install springboot
	$ spring --version
	Spring Boot v{spring-boot-version}
----

If you develop features for the CLI and want easy access to the version you built,
use the following commands:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-{spring-boot-version}-bin/spring-{spring-boot-version}/
	$ sdk default springboot dev
	$ spring --version
	Spring CLI v{spring-boot-version}
----

The preceding instructions install a local instance of `spring` called the `dev`
instance. It points at your target build location, so every time you rebuild Spring Boot,
`spring` is up-to-date.

You can see it by running the following command:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ sdk ls springboot

	================================================================================
	Available Springboot Versions
	================================================================================
	> + dev
	* {spring-boot-version}

	================================================================================
	+ - local version
	* - installed
	> - currently in use
	================================================================================
----



[[getting-started-homebrew-cli-installation]]
==== OSX Homebrew Installation
If you are on a Mac and use http://brew.sh/[Homebrew], you can install the Spring Boot
CLI by using the following commands:

[indent=0]
----
	$ brew tap pivotal/tap
	$ brew install springboot
----

Homebrew installs `spring` to `/usr/local/bin`.

NOTE: If you do not see the formula, your installation of brew might be out-of-date. In
that case, run `brew update` and try again.



[[getting-started-macports-cli-installation]]
==== MacPorts Installation
If you are on a Mac and use http://www.macports.org/[MacPorts], you can install the
Spring Boot CLI by using the following command:

[indent=0]
----
	$ sudo port install spring-boot-cli
----



[[getting-started-cli-command-line-completion]]
==== Command-line Completion
The Spring Boot CLI includes scripts that provide command completion for the
https://en.wikipedia.org/wiki/Bash_%28Unix_shell%29[BASH] and
https://en.wikipedia.org/wiki/Z_shell[zsh] shells. You can `source` the script (also named
`spring`) in any shell or put it in your personal or system-wide bash completion
initialization. On a Debian system, the system-wide scripts are in
`/shell-completion/bash` and all scripts in that directory are executed when a new shell
starts. For example, to run the script manually if you have installed by using SDKMAN!,
use the following commands:

[indent=0]
----
	$ . ~/.sdkman/candidates/springboot/current/shell-completion/bash/spring
	$ spring <HIT TAB HERE>
	  grab  help  jar  run  test  version
----

NOTE: If you install the Spring Boot CLI by using Homebrew or MacPorts, the command-line
completion scripts are automatically registered with your shell.



[[getting-started-scoop-cli-installation]]
==== Windows Scoop Installation
If you are on a Windows and use http://scoop.sh/[Scoop], you can install the Spring Boot
CLI by using the following commands:

[indent=0]
----
	> scoop bucket add extras
	> scoop install springboot
----

Scoop installs `spring` to `~/scoop/apps/springboot/current/bin`.

NOTE: If you do not see the app manifest, your installation of scoop might be out-of-date.
In that case, run `scoop update` and try again.



[[getting-started-cli-example]]
==== Quick-start Spring CLI Example
You can use the following web application to test your installation. To start, create a
file called `app.groovy`, as follows:

[source,groovy,indent=0,subs="verbatim,quotes,attributes"]
----
	@RestController
	class ThisWillActuallyRun {

		@RequestMapping("/")
		String home() {
			"Hello World!"
		}

	}
----

Then run it from a shell, as follows:

[indent=0]
----
	$ spring run app.groovy
----

NOTE: The first run of your application is slow, as dependencies are downloaded.
Subsequent runs are much quicker.

Open `http://localhost:8080` in your favorite web browser. You should see the following
output:

[indent=0]
----
	Hello World!
----



[[getting-started-upgrading-from-an-earlier-version]]
=== Upgrading from an Earlier Version of Spring Boot
If you are upgrading from an earlier 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. To enable that
feature, add the following dependency to your project:

[source,xml,indent=0]
----
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-properties-migrator</artifactId>
		<scope>runtime</scope>
	</dependency>
----

WARNING: Properties that are added late to the environment, such as when using
`@PropertySource`, will not be taken into account.

NOTE: Once you're done with the migration, please make sure to remove this module from
your project's dependencies.

To upgrade an existing CLI installation, use the appropriate package manager command (for
example, `brew upgrade`) or, if you manually installed the CLI, follow the
<<getting-started-manual-cli-installation, standard instructions>>, remembering to update
your `PATH` environment variable to remove any older references.



[[getting-started-first-application]]
== Developing Your First Spring Boot Application
This section describes how to develop a simple "`Hello World!`" web application that
highlights some of Spring Boot's key features. We use Maven to build this project, since
most IDEs support it.

[TIP]
====
The https://spring.io[spring.io] web site contains many "`Getting Started`"
https://spring.io/guides[guides] that use Spring Boot. If you need to solve a specific
problem, check there first.

You can shortcut the steps below by going to https://start.spring.io and choosing the
"Web" starter from the dependencies searcher. Doing so generates a new project structure
so that you can <<getting-started-first-application-code,start coding right away>>. Check
the {spring-initializr-reference}/#user-guide[Spring Initializr documentation] for more
details.
====

Before we begin, open a terminal and run the following commands to ensure that you have
valid versions of Java and Maven installed:

[indent=0]
----
	$ java -version
	java version "1.8.0_102"
	Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
	Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)
----

[indent=0]
----
	$ mvn -v
	Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T16:41:47+00:00)
	Maven home: /usr/local/Cellar/maven/3.3.9/libexec
	Java version: 1.8.0_102, vendor: Oracle Corporation
----

NOTE: This sample needs to be created in its own folder. Subsequent instructions assume
that you have created a suitable folder and that it is your current directory.



[[getting-started-first-application-pom]]
=== Creating the POM
We need to start by creating a Maven `pom.xml` file. The `pom.xml` is the recipe that is
used to build your project. Open your favorite text editor and add the following:

[source,xml,indent=0,subs="verbatim,quotes,attributes"]
----
	<?xml version="1.0" encoding="UTF-8"?>
	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
		<modelVersion>4.0.0</modelVersion>

		<groupId>com.example</groupId>
		<artifactId>myproject</artifactId>
		<version>0.0.1-SNAPSHOT</version>

		<parent>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-parent</artifactId>
			<version>{spring-boot-version}</version>
		</parent>

		<!-- Additional lines to be added here... -->

ifeval::["{spring-boot-repo}" != "release"]
		<!-- (you don't need this if you are using a .RELEASE version) -->
		<repositories>
			<repository>
				<id>spring-snapshots</id>
				<url>https://repo.spring.io/snapshot</url>
				<snapshots><enabled>true</enabled></snapshots>
			</repository>
			<repository>
				<id>spring-milestones</id>
				<url>https://repo.spring.io/milestone</url>
			</repository>
		</repositories>
		<pluginRepositories>
			<pluginRepository>
				<id>spring-snapshots</id>
				<url>https://repo.spring.io/snapshot</url>
			</pluginRepository>
			<pluginRepository>
				<id>spring-milestones</id>
				<url>https://repo.spring.io/milestone</url>
			</pluginRepository>
		</pluginRepositories>
endif::[]
	</project>
----

The preceding listing should give you a working build. You can test it by running `mvn
package` (for now, you can ignore the "`jar will be empty - no content was marked for
inclusion!`" warning).

NOTE: At this point, you could import the project into an IDE (most modern Java IDEs
include built-in support for Maven). For simplicity, we continue to use a plain text
editor for this example.



[[getting-started-first-application-dependencies]]
=== Adding Classpath Dependencies
Spring Boot provides a number of "`Starters`" that let you add jars to your classpath.
Our sample application has already used `spring-boot-starter-parent` in the `parent`
section of the POM. The `spring-boot-starter-parent` is a special starter that provides
useful Maven defaults. It also provides a
<<using-spring-boot.adoc#using-boot-dependency-management,`dependency-management`>>
section so that you can omit `version` tags for "`blessed`" dependencies.

Other "`Starters`" provide dependencies that you are likely to need when developing a
specific type of application. Since we are developing a web application, we add a
`spring-boot-starter-web` dependency. Before that, we can look at what we currently have
by running the following command:

[indent=0]
----
	$ mvn dependency:tree

	[INFO] com.example:myproject:jar:0.0.1-SNAPSHOT
----

The `mvn dependency:tree` command prints a tree representation of your project
dependencies. You can see that `spring-boot-starter-parent` provides no dependencies by
itself. To add the necessary dependencies, edit your `pom.xml` and add the
`spring-boot-starter-web` dependency immediately below the `parent` section:

[source,xml,indent=0,subs="verbatim,quotes,attributes"]
----
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
	</dependencies>
----

If you run `mvn dependency:tree` again, you see that there are now a number of additional
dependencies, including the Tomcat web server and Spring Boot itself.



[[getting-started-first-application-code]]
=== Writing the Code
To finish our application, we need to create a single Java file. By default, Maven
compiles sources from `src/main/java`, so you need to create that folder structure and
then add a file named `src/main/java/Example.java` to contain the following code:

[source,java,indent=0]
----
	import org.springframework.boot.*;
	import org.springframework.boot.autoconfigure.*;
	import org.springframework.web.bind.annotation.*;

	@RestController
	@EnableAutoConfiguration
	public class Example {

		@RequestMapping("/")
		String home() {
			return "Hello World!";
		}

		public static void main(String[] args) throws Exception {
			SpringApplication.run(Example.class, args);
		}

	}
----

Although there is not much code here, quite a lot is going on. We step through the
important parts in the next few sections.



[[getting-started-first-application-annotations]]
==== The @RestController and @RequestMapping Annotations
The first annotation on our `Example` class is `@RestController`. This is known as a
_stereotype_ annotation. It provides hints for people reading the code and for Spring
that the class plays a specific role. In this case, our class is a web `@Controller`, so
Spring considers it when handling incoming web requests.

The `@RequestMapping` annotation provides "`routing`" information. It tells Spring that
any HTTP request with the `/` path should be mapped to the `home` method. The
`@RestController` annotation tells Spring to render the resulting string directly back to
the caller.

TIP: The `@RestController` and `@RequestMapping` annotations are Spring MVC annotations.
(They are not specific to Spring Boot.) See the {spring-reference}web.html#mvc[MVC
section] in the Spring Reference Documentation for more details.



[[getting-started-first-application-auto-configuration]]
==== The @EnableAutoConfiguration Annotation
The second class-level annotation is `@EnableAutoConfiguration`. This annotation tells
Spring Boot to "`guess`" how you want to configure Spring, based on the jar dependencies
that you have added. Since `spring-boot-starter-web` added Tomcat and Spring MVC, the
auto-configuration assumes that you are developing a web application and sets up Spring
accordingly.

.Starters and Auto-configuration
****
Auto-configuration is designed to work well with "`Starters`", but the two concepts are
not directly tied. You are free to pick and choose jar dependencies outside of the
starters. Spring Boot still does its best to auto-configure your application.
****



[[getting-started-first-application-main-method]]
==== The "`main`" Method
The final part of our application is the `main` method. This is just a standard method
that follows the Java convention for an application entry point. Our main method
delegates to Spring Boot's `SpringApplication` class by calling `run`.
`SpringApplication` bootstraps our application, starting Spring, which, in turn, starts
the auto-configured Tomcat web server. We need to pass `Example.class` as an argument to
the `run` method to tell `SpringApplication` which is the primary Spring component. The
`args` array is also passed through to expose any command-line arguments.



[[getting-started-first-application-run]]
=== Running the Example
At this point, your application should work. Since you used the
`spring-boot-starter-parent` POM, you have a useful `run` goal that you can use to start
the application. Type `mvn spring-boot:run` from the root project directory to start the
application. You should see output similar to the following:

[indent=0,subs="attributes"]
----
	$ mvn spring-boot:run

	  .   ____          _            __ _ _
	 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
	( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
	 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
	  '  |____| .__|_| |_|_| |_\__, | / / / /
	 =========|_|==============|___/=/_/_/_/
	 :: Spring Boot ::  (v{spring-boot-version})
	....... . . .
	....... . . . (log output here)
	....... . . .
	........ Started Example in 2.222 seconds (JVM running for 6.514)
----

If you open a web browser to `http://localhost:8080`, you should see the following output:

[indent=0]
----
	Hello World!
----

To gracefully exit the application, press `ctrl-c`.



[[getting-started-first-application-executable-jar]]
=== Creating an Executable Jar
We finish our example by creating a completely self-contained executable jar file that
we could run in production. Executable jars (sometimes called "`fat jars`") are archives
containing your compiled classes along with all of the jar dependencies that your code
needs to run.

.Executable jars and Java
****
Java does not provide a standard way to load nested jar files (jar files that are
themselves contained within a jar). This can be problematic if you are looking to
distribute a self-contained application.

To solve this problem, many developers use "`uber`" jars. An uber jar packages all the
classes from all the application's dependencies into a single archive. The problem with
this approach is that it becomes hard to see which libraries are in your application. It
can also be problematic if the same filename is used (but with different content) in
multiple jars.

Spring Boot takes a <<appendix-executable-jar-format.adoc#executable-jar, different
approach>> and lets you actually nest jars directly.
****

To create an executable jar, we need to add the `spring-boot-maven-plugin` to our
`pom.xml`. To do so, insert the following lines just below the `dependencies` section:

[source,xml,indent=0,subs="verbatim,quotes,attributes"]
----
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
----

NOTE: The `spring-boot-starter-parent` POM includes `<executions>` configuration to bind
the `repackage` goal. If you do not use the parent POM, you need to declare this
configuration yourself. See the {spring-boot-maven-plugin-site}/usage.html[plugin
documentation] for details.

Save your `pom.xml` and run `mvn package` from the command line, as follows:

[indent=0,subs="attributes"]
----
	$ mvn package

	[INFO] Scanning for projects...
	[INFO]
	[INFO] ------------------------------------------------------------------------
	[INFO] Building myproject 0.0.1-SNAPSHOT
	[INFO] ------------------------------------------------------------------------
	[INFO] .... ..
	[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myproject ---
	[INFO] Building jar: /Users/developer/example/spring-boot-example/target/myproject-0.0.1-SNAPSHOT.jar
	[INFO]
	[INFO] --- spring-boot-maven-plugin:{spring-boot-version}:repackage (default) @ myproject ---
	[INFO] ------------------------------------------------------------------------
	[INFO] BUILD SUCCESS
	[INFO] ------------------------------------------------------------------------
----

If you look in the `target` directory, you should see `myproject-0.0.1-SNAPSHOT.jar`. The
file should be around 10 MB in size. If you want to peek inside, you can use `jar tvf`,
as follows:

[indent=0]
----
	$ jar tvf target/myproject-0.0.1-SNAPSHOT.jar
----

You should also see a much smaller file named `myproject-0.0.1-SNAPSHOT.jar.original` in
the `target` directory. This is the original jar file that Maven created before it was
repackaged by Spring Boot.

To run that application, use the `java -jar` command, as follows:

[indent=0,subs="attributes"]
----
	$ java -jar target/myproject-0.0.1-SNAPSHOT.jar

	  .   ____          _            __ _ _
	 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
	( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
	 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
	  '  |____| .__|_| |_|_| |_\__, | / / / /
	 =========|_|==============|___/=/_/_/_/
	 :: Spring Boot ::  (v{spring-boot-version})
	....... . . .
	....... . . . (log output here)
	....... . . .
	........ Started Example in 2.536 seconds (JVM running for 2.864)
----

As before, to exit the application, press `ctrl-c`.



[[getting-started-whats-next]]
== What to Read Next
Hopefully, this section provided some of the Spring Boot basics and got you on your way
to writing your own applications. If you are a task-oriented type of developer, you might
want to jump over to https://spring.io and check out some of the
https://spring.io/guides/[getting started] guides that solve specific "`How do I do that
with Spring?`" problems. We also have Spring Boot-specific
"`<<howto.adoc#howto, How-to>>`" reference documentation.

The https://github.com/{github-repo}[Spring Boot repository] also has a
{github-code}/spring-boot-samples[bunch of samples] you can run. The samples are
independent of the rest of the code (that is, you do not need to build the rest to run or
use the samples).

Otherwise, the next logical step is to read _<<using-spring-boot.adoc#using-boot>>_. If
you are really impatient, you could also jump ahead and read about
_<<spring-boot-features.adoc#boot-features, Spring Boot features>>_.
