1. Introduction

The Spring Boot Maven Plugin provides Spring Boot support in Apache Maven. It allows you to package executable jar or war archives, run Spring Boot applications, generate build information and start your Spring Boot application prior to running integration tests.

2. Getting Started

To use the Spring Boot Maven Plugin, include the appropriate XML in the plugins section of your pom.xml, as shown in the following example:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<!-- ... -->
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

If you use a milestone or snapshot release, you also need to add the appropriate pluginRepository elements, as shown in the following listing:

<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>

3. Using the Plugin

Maven users can inherit from the spring-boot-starter-parent project to obtain sensible defaults. The parent project provides the following features:

  • Java 1.8 as the default compiler level.

  • UTF-8 source encoding.

  • A dependency management section, inherited from the spring-boot-dependencies POM, that manages the versions of common dependencies. This dependency management lets you omit <version> tags for those dependencies when used in your own POM.

  • An execution of the repackage goal with a repackage execution id.

  • Sensible resource filtering.

  • Sensible plugin configuration (Git commit ID, and shade).

  • Sensible resource filtering for application.properties and application.yml including profile-specific files (for example, application-dev.properties and application-dev.yml)

Since the application.properties and application.yml files accept Spring style placeholders (${…​}), the Maven filtering is changed to use @[email protected] placeholders. (You can override that by setting a Maven property called resource.delimiter.)

3.1. Inheriting the Starter Parent POM

To configure your project to inherit from the spring-boot-starter-parent, set the parent as follows:

<!-- Inherit defaults from Spring Boot -->
<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>2.4.0-SNAPSHOT</version>
</parent>
You should need to specify only the Spring Boot version number on this dependency. If you import additional starters, you can safely omit the version number.

With that setup, you can also override individual dependencies by overriding a property in your own project. For instance, to use a different version of the SLF4J library and the Spring Data release train, you would add the following to your pom.xml:

<properties>
	<slf4j.version>1.7.30</slf4j.version>
	<spring-data-releasetrain.version>Moore-SR6</spring-data-releasetrain.version>
</properties>

Browse the Dependency versions Appendix in the Spring Boot reference for a complete list of dependency version properties.

3.2. Using Spring Boot without the Parent POM

There may be reasons for you not to inherit from the spring-boot-starter-parent POM. You may have your own corporate standard parent that you need to use or you may prefer to explicitly declare all your Maven configuration.

If you do not want to use the spring-boot-starter-parent, you can still keep the benefit of the dependency management (but not the plugin management) by using an import scoped dependency, as follows:

<dependencyManagement>
	<dependencies>
		<dependency>
			<!-- Import dependency management from Spring Boot -->
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-dependencies</artifactId>
			<version>2.4.0-SNAPSHOT</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
	</dependencies>
</dependencyManagement>

The preceding sample setup does not let you override individual dependencies by using properties, as explained above. To achieve the same result, you need to add entries in the dependencyManagement section of your project before the spring-boot-dependencies entry. For instance, to use a different version of the SLF4J library and the Spring Data release train, you could add the following elements to your pom.xml:

<dependencyManagement>
	<dependencies>
		<!-- Override SLF4J provided by Spring Boot -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.30</version>
		</dependency>
		<!-- Override Spring Data release train provided by Spring Boot -->
		<dependency>
			<groupId>org.springframework.data</groupId>
			<artifactId>spring-data-releasetrain</artifactId>
			<version>2020.0.0-SR1</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-dependencies</artifactId>
			<version>2.4.0-SNAPSHOT</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
	</dependencies>
</dependencyManagement>

3.3. Overriding settings on the command-line

The plugin offers a number of user properties, starting with spring-boot, to let you customize the configuration from the command-line.

For instance, you could tune the profiles to enable when running the application as follows:

$ mvn spring-boot:run -Dspring-boot.run.profiles=dev,local

If you want to both have a default while allowing it to be overridden on the command-line, you should use a combination of a user-provided project property and MOJO configuration.

<project>
    <properties>
        <app.profiles>local,dev</app.profiles>
    </properties>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<profiles>${app.profiles}</profiles>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

The above makes sure that local and dev are enabled by default. Now a dedicated property has been exposed, this can be overridden on the command-line as well:

$ mvn spring-boot:run -Dapp.profiles=test

4. Goals

The Spring Boot Plugin has the following goals:

Goal Description

spring-boot:build-image

Package an application into a OCI image using a buildpack.

spring-boot:build-info

Generate a build-info.properties file based the content of the current MavenProject.

spring-boot:help

Display help information on spring-boot-maven-plugin. Call mvn spring-boot:help -Ddetail=true -Dgoal=<goal-name> to display parameter details.

spring-boot:repackage

Repackage existing JAR and WAR archives so that they can be executed from the command line using java -jar. With layout=NONE can also be used simply to package a JAR with nested dependencies (and no main class, so not executable).

spring-boot:run

Run an application in place.

spring-boot:start

Start a spring application. Contrary to the run goal, this does not block and allows other goals to operate on the application. This goal is typically used in integration test scenario where the application is started before a test suite and stopped after.

spring-boot:stop

Stop an application that has been started by the "start" goal. Typically invoked once a test suite has completed.

5. Packaging Executable Archives

The plugin can create executable archives (jar files and war files) that contain all of an application’s dependencies and can then be run with java -jar.

Packaging an executable archive is performed by the repackage goal, as shown in the following example:

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
			<executions>
				<execution>
					<goals>
						<goal>repackage</goal>
					</goals>
				</execution>
			</executions>
		</plugin>
	</plugins>
</build>
If you are using spring-boot-starter-parent, such execution is already pre-configured with a repackage execution ID so that only the plugin definition should be added.

The example above repackages a jar or war archive that is built during the package phase of the Maven lifecycle, including any provided dependencies that are defined in the project. If some of these dependencies need to be excluded, you can use one of the exclude options; see the dependency exclusion for more details.

The original (i.e. non-executable) artifact is renamed to .original by default but it is also possible to keep the original artifact using a custom classifier.

The outputFileNameMapping feature of the maven-war-plugin is currently not supported.

Devtools is automatically excluded by default (you can control that using the excludeDevtools property). In order to make that work with war packaging, the spring-boot-devtools dependency must be set as optional or with the provided scope.

The plugin rewrites your manifest, and in particular it manages the Main-Class and Start-Class entries. If the defaults don’t work you have to configure the values in the Spring Boot plugin, not in the jar plugin. The Main-Class in the manifest is controlled by the layout property of the Spring Boot plugin, as shown in the following example:

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
			<configuration>
				<mainClass>${start.class}</mainClass>
				<layout>ZIP</layout>
			</configuration>
			<executions>
				<execution>
					<goals>
						<goal>repackage</goal>
					</goals>
				</execution>
			</executions>
		</plugin>
	</plugins>
</build>

The layout property defaults to a value determined by the archive type (jar or war). The following layouts are available:

  • JAR: regular executable JAR layout.

  • WAR: executable WAR layout. provided dependencies are placed in WEB-INF/lib-provided to avoid any clash when the war is deployed in a servlet container.

  • ZIP (alias to DIR): similar to the JAR layout using PropertiesLauncher.

  • NONE: Bundle all dependencies and project resources. Does not bundle a bootstrap loader.

5.1. Layered Jars

A repackaged jar contains the application’s classes and dependencies in BOOT-INF/classes and BOOT-INF/lib respectively. For cases where a docker image needs to be built from the contents of the jar, it’s useful to be able to separate these directories further so that they can be written into distinct layers.

Layered jars use the same layout as regular repackaged jars, but include an additional meta-data file that describes each layer.

By default, the following layers are defined:

  • dependencies for any dependency whose version does not contain SNAPSHOT.

  • spring-boot-loader for the jar loader classes.

  • snapshot-dependencies for any dependency whose version contains SNAPSHOT.

  • application for local module dependencies, application classes, and resources.

Module dependencies are identified by looking at all of the modules that are part of the current build. If a module dependency can only be resolved because it has been installed into Maven’s local cache and it is not part of the current build, it will be identified as regular dependency.

The layers order is important as it determines how likely previous layers can be cached when part of the application changes. The default order is dependencies, spring-boot-loader, snapshot-dependencies, application. Content that is least likely to change should be added first, followed by layers that are more likely to change.

The repackaged jar includes the layers.idx file by default. To disable this feature, you can do so in the following manner:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<layers>
						<enabled>false</enabled>
					</layers>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

5.1.1. Custom Layers Configuration

Depending on your application, you may want to tune how layers are created and add new ones. This can be done using a separate configuration file that should be registered as shown below:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<layers>
						<enabled>true</enabled>
						<configuration>${project.basedir}/src/layers.xml</configuration>
					</layers>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

The configuration file describes how the jar can be separated into layers, and the order of those layers. The following example shows how the default ordering described above can be defined explicitly:

<layers xmlns="http://www.springframework.org/schema/boot/layers"
					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
                      https://www.springframework.org/schema/boot/layers/layers-2.4.xsd">
	<application>
		<into layer="spring-boot-loader">
			<include>org/springframework/boot/loader/**</include>
		</into>
		<into layer="application" />
	</application>
	<dependencies>
		<into layer="application">
			<includeModuleDependencies />
		</into>
		<into layer="snapshot-dependencies">
			<include>*:*:*SNAPSHOT</include>
		</into>
		<into layer="dependencies" />
	</dependencies>
	<layerOrder>
		<layer>dependencies</layer>
		<layer>spring-boot-loader</layer>
		<layer>snapshot-dependencies</layer>
		<layer>application</layer>
    </layerOrder>
</layers>

The layers XML format is defined in three sections:

  • The <application> block defines how the application classes and resources should be layered.

  • The <dependencies> block defines how dependencies should be layered.

  • The <layerOrder> block defines the order that the layers should be written.

Nested <into> blocks are used within <application> and <dependencies> sections to claim content for a layer. The blocks are evaluated in the order that they are defined, from top to bottom. Any content not claimed by an earlier block remains available for subsequent blocks to consider.

The <into> block claims content using nested <include> and <exclude> elements. The <application> section uses Ant-style patch matching for include/exclude expressions. The <dependencies> section uses group:artifact[:version] patterns. It also provides <includeModuleDependencies /> and <excludeModuleDependencies /> elements that can be used to include or exclude local module dependencies.

If no <include> is defined, then all content (not claimed by an earlier block) is considered.

If no <exclude> is defined, then no exclusions are applied.

Looking at the <dependencies> example above, we can see that the first <into> will claim all module dependencies for the application.layer. The next <into> will claim all SNAPSHOT dependencies for the snapshot-dependencies layer. The final <into> will claim anything left (in this case, any dependency that is not a SNAPSHOT) for the dependencies layer.

The <application> block has similar rules. First claiming org/springframework/boot/loader/** content for the spring-boot-loader layer. Then claiming any remaining classes and resources for the application layer.

The order that <into> blocks are defined is often different from the order that the layers are written. For this reason the <layerOrder> element must always be included and must cover all layers referenced by the <into> blocks.

5.2. spring-boot:repackage

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Repackage existing JAR and WAR archives so that they can be executed from the command line using java -jar. With layout=NONE can also be used simply to package a JAR with nested dependencies (and no main class, so not executable).

5.2.1. Required parameters

Name Type Default

outputDirectory

File

${project.build.directory}

5.2.2. Optional parameters

Name Type Default

attach

boolean

true

classifier

String

embeddedLaunchScript

File

embeddedLaunchScriptProperties

Properties

excludeDevtools

boolean

true

excludeGroupIds

String

excludes

List

executable

boolean

false

includeSystemScope

boolean

false

includes

List

layers

Layers

layout

LayoutType

layoutFactory

LayoutFactory

mainClass

String

outputTimestamp

String

${project.build.outputTimestamp}

requiresUnpack

List

skip

boolean

false

5.2.3. Parameter details

attach

Attach the repackaged archive to be installed into your local Maven repository or deployed to a remote repository. If no classifier has been configured, it will replace the normal jar. If a classifier has been configured such that the normal jar and the repackaged jar are different, it will be attached alongside the normal jar. When the property is set to false, the repackaged archive will not be installed or deployed.

Name

attach

Type

boolean

Default value

true

User property

Since

1.4.0

classifier

Classifier to add to the repackaged archive. If not given, the main artifact will be replaced by the repackaged archive. If given, the classifier will also be used to determine the source archive to repackage: if an artifact with that classifier already exists, it will be used as source and replaced. If no such artifact exists, the main artifact will be used as source and the repackaged archive will be attached as a supplemental artifact with that classifier. Attaching the artifact allows to deploy it alongside to the original one, see $1[$2].

Name

classifier

Type

java.lang.String

Default value

User property

Since

1.0.0

embeddedLaunchScript

The embedded launch script to prepend to the front of the jar if it is fully executable. If not specified the 'Spring Boot' default script will be used.

Name

embeddedLaunchScript

Type

java.io.File

Default value

User property

Since

1.3.0

embeddedLaunchScriptProperties

Properties that should be expanded in the embedded launch script.

Name

embeddedLaunchScriptProperties

Type

java.util.Properties

Default value

User property

Since

1.3.0

excludeDevtools

Exclude Spring Boot devtools from the repackaged archive.

Name

excludeDevtools

Type

boolean

Default value

true

User property

spring-boot.repackage.excludeDevtools

Since

1.3.0

excludeGroupIds

Comma separated list of groupId names to exclude (exact match).

Name

excludeGroupIds

Type

java.lang.String

Default value

User property

spring-boot.excludeGroupIds

Since

1.1.0

excludes

Collection of artifact definitions to exclude. The Exclude element defines mandatory groupId and artifactId properties and an optional classifier property.

Name

excludes

Type

java.util.List

Default value

User property

spring-boot.excludes

Since

1.1.0

executable

Make a fully executable jar for *nix machines by prepending a launch script to the jar. <p> Currently, some tools do not accept this format so you may not always be able to use this technique. For example, jar -xf may silently fail to extract a jar or war that has been made fully-executable. It is recommended that you only enable this option if you intend to execute it directly, rather than running it with java -jar or deploying it to a servlet container.

Name

executable

Type

boolean

Default value

false

User property

Since

1.3.0

includeSystemScope

Include system scoped dependencies.

Name

includeSystemScope

Type

boolean

Default value

false

User property

Since

1.4.0

includes

Collection of artifact definitions to include. The Include element defines mandatory groupId and artifactId properties and an optional mandatory groupId and artifactId properties and an optional classifier property.

Name

includes

Type

java.util.List

Default value

User property

spring-boot.includes

Since

1.2.0

layers

Layer configuration with options to disable layer creation, exclude layer tools jar, and provide a custom layers configuration file.

Name

layers

Type

org.springframework.boot.maven.Layers

Default value

User property

Since

2.3.0

layout

The type of archive (which corresponds to how the dependencies are laid out inside it). Possible values are JAR, WAR, ZIP, DIR, NONE. Defaults to a guess based on the archive type.

Name

layout

Type

org.springframework.boot.maven.AbstractPackagerMojo$LayoutType

Default value

User property

spring-boot.repackage.layout

Since

1.0.0

layoutFactory

The layout factory that will be used to create the executable archive if no explicit layout is set. Alternative layouts implementations can be provided by 3rd parties.

Name

layoutFactory

Type

org.springframework.boot.loader.tools.LayoutFactory

Default value

User property

Since

1.5.0

mainClass

The name of the main class. If not specified the first compiled class found that contains a main method will be used.

Name

mainClass

Type

java.lang.String

Default value

User property

Since

1.0.0

outputDirectory

Directory containing the generated archive.

Name

outputDirectory

Type

java.io.File

Default value

${project.build.directory}

User property

Since

1.0.0

outputTimestamp

Timestamp for reproducible output archive entries, either formatted as ISO 8601 (yyyy-MM-dd’T’HH:mm:ssXXX) or an int representing seconds since the epoch. Not supported with war packaging.

Name

outputTimestamp

Type

java.lang.String

Default value

${project.build.outputTimestamp}

User property

Since

2.3.0

requiresUnpack

A list of the libraries that must be unpacked from fat jars in order to run. Specify each library as a <dependency> with a <groupId> and a <artifactId> and they will be unpacked at runtime.

Name

requiresUnpack

Type

java.util.List

Default value

User property

Since

1.1.0

skip

Skip the execution.

Name

skip

Type

boolean

Default value

false

User property

spring-boot.repackage.skip

Since

1.2.0

5.3. Examples

5.3.1. Custom Classifier

By default, the repackage goal replaces the original artifact with the repackaged one. That is a sane behavior for modules that represent an application but if your module is used as a dependency of another module, you need to provide a classifier for the repackaged one. The reason for that is that application classes are packaged in BOOT-INF/classes so that the dependent module cannot load a repackaged jar’s classes.

If that is the case or if you prefer to keep the original artifact and attach the repackaged one with a different classifier, configure the plugin as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<goals>
							<goal>repackage</goal>
						</goals>
						<configuration>
							<classifier>exec</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

If you are using spring-boot-starter-parent, the repackage goal is executed automatically in an execution with id repackage. In that setup, only the configuration should be specified, as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<configuration>
							<classifier>exec</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

This configuration will generate two artifacts: the original one and the repackaged counter part produced by the repackage goal. Both will be installed/deployed transparently.

You can also use the same configuration if you want to repackage a secondary artifact the same way the main artifact is replaced. The following configuration installs/deploys a single task classified artifact with the repackaged application:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-jar-plugin</artifactId>
				<executions>
					<execution>
						<goals>
							<goal>jar</goal>
						</goals>
						<phase>package</phase>
						<configuration>
							<classifier>task</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<goals>
							<goal>repackage</goal>
						</goals>
						<configuration>
							<classifier>task</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

As both the maven-jar-plugin and the spring-boot-maven-plugin runs at the same phase, it is important that the jar plugin is defined first (so that it runs before the repackage goal). Again, if you are using spring-boot-starter-parent, this can be simplified as follows:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-jar-plugin</artifactId>
				<executions>
					<execution>
						<id>default-jar</id>
						<configuration>
							<classifier>task</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<configuration>
							<classifier>task</classifier>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

5.3.2. Custom Name

If you need the repackaged jar to have a different local name than the one defined by the artifactId attribute of the project, use the standard finalName, as shown in the following example:

<project>
	<build>
		<finalName>my-app</finalName>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<goals>
							<goal>repackage</goal>
						</goals>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

This configuration will generate the repackaged artifact in target/my-app.jar.

5.3.3. Local Repackaged Artifact

By default, the repackage goal replaces the original artifact with the executable one. If you need to only deploy the original jar and yet be able to run your app with the regular file name, configure the plugin as follows:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<goals>
							<goal>repackage</goal>
						</goals>
						<configuration>
							<attach>false</attach>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

This configuration generates two artifacts: the original one and the executable counter part produced by the repackage goal. Only the original one will be installed/deployed.

5.3.4. Custom Layout

Spring Boot repackages the jar file for this project using a custom layout factory defined in the additional jar file, provided as a dependency to the build plugin:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>repackage</id>
						<goals>
							<goal>repackage</goal>
						</goals>
						<configuration>
							<layoutFactory implementation="com.example.CustomLayoutFactory">
								<customProperty>value</customProperty>
							</layoutFactory>
						</configuration>
					</execution>
				</executions>
				<dependencies>
					<dependency>
						<groupId>com.example</groupId>
						<artifactId>custom-layout</artifactId>
						<version>0.0.1.BUILD-SNAPSHOT</version>
					</dependency>
				</dependencies>
			</plugin>
		</plugins>
	</build>
</project>

The layout factory is provided as an implementation of LayoutFactory (from spring-boot-loader-tools) explicitly specified in the pom. If there is only one custom LayoutFactory on the plugin classpath and it is listed in META-INF/spring.factories then it is unnecessary to explicitly set it in the plugin configuration.

Layout factories are always ignored if an explicit layout is set.

5.3.5. Dependency Exclusion

By default, both the repackage and the run goals will include any provided dependencies that are defined in the project. A Spring Boot project should consider provided dependencies as "container" dependencies that are required to run the application.

Some of these dependencies may not be required at all and should be excluded from the executable jar. For consistency, they should not be present either when running the application.

There are two ways one can exclude a dependency from being packaged/used at runtime:

  • Exclude a specific artifact identified by groupId and artifactId, optionally with a classifier if needed.

  • Exclude any artifact belonging to a given groupId.

The following example excludes com.foo:bar, and only that artifact:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<excludes>
						<exclude>
							<groupId>com.foo</groupId>
							<artifactId>bar</artifactId>
						</exclude>
					</excludes>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

This example excludes any artifact belonging to the com.foo group:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<excludeGroupIds>com.foo</excludeGroupIds>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

5.3.6. Layered Jar Tools

When a layered jar is created, the spring-boot-jarmode-layertools jar will be added as a dependency to your jar. With this jar on the classpath, you can launch your application in a special mode which allows the bootstrap code to run something entirely different from your application, for example, something that extracts the layers. If you wish to exclude this dependency, you can do so in the following manner:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<layers>
						<includeLayerTools>false</includeLayerTools>
					</layers>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

5.3.7. Custom Layers Configuration

The default setup splits dependencies into snapshot and non-snapshot, however, you may have more complex rules. For example, you may want to isolate company-specific dependencies of your project in a dedicated layer. The following layers.xml configuration shown one such setup:

<layers xmlns="http://www.springframework.org/schema/boot/layers"
					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
					  https://www.springframework.org/schema/boot/layers/layers-2.4.xsd">
	<application>
		<into layer="spring-boot-loader">
			<include>org/springframework/boot/loader/**</include>
		</into>
		<into layer="application" />
	</application>
	<dependencies>
		<into layer="snapshot-dependencies">
			<include>*:*:*SNAPSHOT</include>
		</into>
		<into layer="company-dependencies">
			<include>com.acme:*</include>
		</into>
		<into layer="dependencies"/>
	</dependencies>
	<layerOrder>
		<layer>dependencies</layer>
		<layer>spring-boot-loader</layer>
		<layer>snapshot-dependencies</layer>
		<layer>company-dependencies</layer>
		<layer>application</layer>
	</layerOrder>
</layers>

The configuration above creates an additional company-dependencies layer with all libraries with the com.acme groupId.

6. Packaging OCI Images

The plugin can create an OCI image using Cloud Native Buildpacks (CNB). Images can be built using the build-image goal.

For security reasons, images build and run as non-root users. See the CNB specification for more details.

The easiest way to get started is to invoke mvn spring-boot:build-image on a project. It is possible to automate the creation of an image whenever the package phase is invoked, as shown in the following example:

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
			<executions>
				<execution>
					<goals>
						<goal>build-image</goal>
					</goals>
				</execution>
			</executions>
		</plugin>
	</plugins>
</build>
While the buildpack runs from an executable archive, it is not necessary to execute the repackage goal first as the executable archive is created automatically if necessary. When the build-image repackages the application, it applies the same settings as the repackage goal would, i.e. dependencies can be excluded using one of the exclude options, and Devtools is automatically excluded by default (you can control that using the excludeDevtools property).

6.1. Docker Daemon

The build-image goal requires access to a Docker daemon. By default, it will communicate with a Docker daemon over a local connection. This works with Docker Engine on all supported platforms without configuration.

Environment variables can be set to configure the build-image goal to use the Docker daemon provided by minikube. The following table shows the environment variables and their values:

Environment variable Description

DOCKER_HOST

URL containing the host and port for the Docker daemon - e.g. tcp://192.168.99.100:2376

DOCKER_TLS_VERIFY

Enable secure HTTPS protocol when set to 1 (optional)

DOCKER_CERT_PATH

Path to certificate and key files for HTTPS (required if DOCKER_TLS_VERIFY=1, ignored otherwise)

On Linux and macOS, these environment variables can be set using the command eval $(minikube docker-env) after minikube has been started.

Docker daemon connection information can also be provided using docker parameters in the plugin configuration. The following table summarizes the available parameters:

Parameter Description

host

URL containing the host and port for the Docker daemon - e.g. tcp://192.168.99.100:2376

tlsVerify

Enable secure HTTPS protocol when set to true (optional)

certPath

Path to certificate and key files for HTTPS (required if tlsVerify is true, ignored otherwise)

For more details, see also examples.

6.2. Docker Registry

If the Docker images specified by the builder or runImage parameters are stored in a private Docker image registry that requires authentication, the authentication credentials can be provided using docker.builderRegistry parameters.

If the generated Docker image is to be published to a Docker image registry, the authentication credentials can be provided using docker.publishRegistry parameters.

Parameters are provided for user authentication or identity token authentication. Consult the documentation for the Docker registry being used to store images for further information on supported authentication methods.

The following table summarizes the available parameters for docker.builderRegistry and docker.publishRegistry:

Parameter Description

username

Username for the Docker image registry user. Required for user authentication.

password

Password for the Docker image registry user. Required for user authentication.

url

Address of the Docker image registry. Optional for user authentication.

email

E-mail address for the Docker image registry user. Optional for user authentication.

token

Identity token for the Docker image registry user. Required for token authentication.

For more details, see also examples.

6.3. Image Customizations

The plugin invokes a builder to orchestrate the generation of an image. The builder includes multiple buildpacks that can inspect the application to influence the generated image. By default, the plugin chooses a builder image. The name of the generated image is deduced from project properties.

The image parameter allows configuration of the builder and how it should operate on the project. The following table summarizes the available parameters and their default values:

Parameter Description User property Default value

builder

Name of the Builder image to use.

spring-boot.build-image.builder

paketobuildpacks/builder:base

runImage

Name of the run image to use.

spring-boot.build-image.runImage

No default value, indicating the run image specified in Builder metadata should be used.

name

Image name for the generated image.

spring-boot.build-image.imageName

docker.io/library/${project.artifactId}:${project.version}

pullPolicy

Policy used to determine when to pull the builder and run images from the registry. Acceptable values are ALWAYS, NEVER, and IF_NOT_PRESENT.

spring-boot.build-image.pullPolicy

ALWAYS

env

Environment variables that should be passed to the builder.

cleanCache

Whether to clean the cache before building.

spring-boot.build-image.cleanCache

false

verboseLogging

Enables verbose logging of builder operations.

false

publish

Whether to publish the generated image to a Docker registry.

spring-boot.build-image.publish

false

The plugin detects the target Java compatibility of the project using the compiler’s plugin configuration or the maven.compiler.target property. When using the default Paketo builder and buildpacks, the plugin instructs the buildpacks to install the same Java version. You can override this behaviour as shown in the builder configuration examples.

For more details, see also examples.

6.4. spring-boot:build-image

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Package an application into a OCI image using a buildpack.

6.4.1. Required parameters

Name Type Default

sourceDirectory

File

${project.build.directory}

6.4.2. Optional parameters

Name Type Default

classifier

String

docker

Docker

excludeDevtools

boolean

true

excludeGroupIds

String

excludes

List

image

Image

includeSystemScope

boolean

false

includes

List

layers

Layers

layout

LayoutType

layoutFactory

LayoutFactory

mainClass

String

skip

boolean

false

6.4.3. Parameter details

classifier

Classifier used when finding the source jar.

Name

classifier

Type

java.lang.String

Default value

User property

Since

2.3.0

docker

Docker configuration options.

Name

docker

Type

org.springframework.boot.maven.Docker

Default value

User property

Since

2.4.0

excludeDevtools

Exclude Spring Boot devtools from the repackaged archive.

Name

excludeDevtools

Type

boolean

Default value

true

User property

spring-boot.repackage.excludeDevtools

Since

1.3.0

excludeGroupIds

Comma separated list of groupId names to exclude (exact match).

Name

excludeGroupIds

Type

java.lang.String

Default value

User property

spring-boot.excludeGroupIds

Since

1.1.0

excludes

Collection of artifact definitions to exclude. The Exclude element defines mandatory groupId and artifactId properties and an optional classifier property.

Name

excludes

Type

java.util.List

Default value

User property

spring-boot.excludes

Since

1.1.0

image

Image configuration, with builder, runImage, name, env, cleanCache, verboseLogging, pullPolicy, and publish options.

Name

image

Type

org.springframework.boot.maven.Image

Default value

User property

Since

2.3.0

includeSystemScope

Include system scoped dependencies.

Name

includeSystemScope

Type

boolean

Default value

false

User property

Since

1.4.0

includes

Collection of artifact definitions to include. The Include element defines mandatory groupId and artifactId properties and an optional mandatory groupId and artifactId properties and an optional classifier property.

Name

includes

Type

java.util.List

Default value

User property

spring-boot.includes

Since

1.2.0

layers

Layer configuration with options to disable layer creation, exclude layer tools jar, and provide a custom layers configuration file.

Name

layers

Type

org.springframework.boot.maven.Layers

Default value

User property

Since

2.3.0

layout

The type of archive (which corresponds to how the dependencies are laid out inside it). Possible values are JAR, WAR, ZIP, DIR, NONE. Defaults to a guess based on the archive type.

Name

layout

Type

org.springframework.boot.maven.AbstractPackagerMojo$LayoutType

Default value

User property

spring-boot.repackage.layout

Since

1.0.0

layoutFactory

The layout factory that will be used to create the executable archive if no explicit layout is set. Alternative layouts implementations can be provided by 3rd parties.

Name

layoutFactory

Type

org.springframework.boot.loader.tools.LayoutFactory

Default value

User property

Since

1.5.0

mainClass

The name of the main class. If not specified the first compiled class found that contains a main method will be used.

Name

mainClass

Type

java.lang.String

Default value

User property

Since

1.0.0

skip

Skip the execution.

Name

skip

Type

boolean

Default value

false

User property

spring-boot.build-image.skip

Since

2.3.0

sourceDirectory

Directory containing the JAR.

Name

sourceDirectory

Type

java.io.File

Default value

${project.build.directory}

User property

Since

2.3.0

6.5. Examples

6.5.1. Custom Image Builder

If you need to customize the builder used to create the image or the run image used to launch the built image, configure the plugin as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<image>
						<builder>mine/java-cnb-builder</builder>
						<runImage>mine/java-cnb-run</runImage>
					</image>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

This configuration will use a builder image with the name mine/java-cnb-builder and the tag latest, and the run image named mine/java-cnb-run and the tag latest.

The builder and run image can be specified on the command line as well, as shown in this example:

$ mvn spring-boot:build-image -Dspring-boot.build-image.builder=mine/java-cnb-builder -Dspring-boot.build-image.runImage=mine/java-cnb-run

6.5.2. Builder Configuration

If the builder exposes configuration options using environment variables, those can be set using the env attributes.

The following is an example of configuring the JVM version used by the Paketo Java buildpacks at build time:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<image>
						<env>
							<BP_JVM_VERSION>8.*</BP_JVM_VERSION>
						</env>
					</image>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

In a similar way, Paketo Java buildpacks support configuring JVM runtime behavior. Refer to the Paketo documentation for additional configuration options supported by Paketo Java buildpacks.

If there is a network proxy between the Docker daemon the builder runs in and network locations that buildpacks download artifacts from, you will need to configure the builder to use the proxy. When using the Paketo builder, this can be accomplished by setting the HTTPS_PROXY and/or HTTP_PROXY environment variables as show in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<image>
						<env>
							<HTTP_PROXY>http://proxy.example.com</HTTP_PROXY>
							<HTTPS_PROXY>https://proxy.example.com</HTTPS_PROXY>
						</env>
					</image>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

6.5.3. Custom Image Name

By default, the image name is inferred from the artifactId and the version of the project, something like docker.io/library/${project.artifactId}:${project.version}. You can take control over the name, as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<image>
						<name>example.com/library/${project.artifactId}</name>
					</image>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>
This configuration does not provide an explicit tag so latest is used. It is possible to specify a tag as well, either using ${project.version}, any property available in the build or a hardcoded version.

The image name can be specified on the command line as well, as shown in this example:

$ mvn spring-boot:build-image -Dspring-boot.build-image.imageName=example.com/library/my-app:v1

6.5.4. Image Publishing

The generated image can be published to a Docker registry by enabling a publish option and configuring authentication for the registry using docker.publishRegistry parameters.

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<image>
						<name>docker.example.com/library/${project.artifactId}</name>
						<publish>true</publish>
					</image>
					<docker>
						<publishRegistry>
							<username>user</username>
							<password>secret</password>
							<url>https://docker.example.com/v1/</url>
							<email>[email protected]</email>
						</publishRegistry>
					</docker>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

The publish option can be specified on the command line as well, as shown in this example:

$ mvn spring-boot:build-image -Dspring-boot.build-image.imageName=docker.example.com/library/my-app:v1 -Dspring-boot.build-image.publish=true

6.5.5. Docker Configuration

If you need the plugin to communicate with the Docker daemon using a remote connection instead of the default local connection, the connection details can be provided using docker parameters as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<docker>
						<host>tcp://192.168.99.100:2376</host>
						<tlsVerify>true</tlsVerify>
						<certPath>/home/user/.minikube/certs</certPath>
					</docker>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

If the builder or run image are stored in a private Docker registry that supports user authentication, authentication details can be provided using docker.builderRegistry parameters as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<docker>
						<builderRegistry>
							<username>user</username>
							<password>secret</password>
							<url>https://docker.example.com/v1/</url>
							<email>[email protected]</email>
						</builderRegistry>
					</docker>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

If the builder or run image is stored in a private Docker registry that supports token authentication, the token value can be provided using docker.builderRegistry parameters as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<docker>
						<builderRegistry>
							<token>9cbaf023786cd7...</token>
						</builderRegistry>
					</docker>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

7. Running your Application with Maven

The plugin includes a run goal which can be used to launch your application from the command line, as shown in the following example:

$ mvn spring-boot:run

Application arguments can be specified using the arguments parameter, see using application arguments for more details.

By default the application is executed in a forked process and setting properties on the command-line will not affect the application. If you need to specify some JVM arguments (i.e. for debugging purposes), you can use the jvmArguments parameter, see Debug the application for more details. There is also explicit support for system properties and environment variables.

As enabling a profile is quite common, there is dedicated profiles property that offers a shortcut for -Dspring-boot.run.jvmArguments="-Dspring.profiles.active=dev", see Specify active profiles.

Although this is not recommended, it is possible to execute the application directly from the Maven JVM by disabling the fork property. Doing so means that the jvmArguments, systemPropertyVariables, environmentVariables and agents options are ignored.

Spring Boot devtools is a module to improve the development-time experience when working on Spring Boot applications. To enable it, just add the following dependency to your project:

<dependencies>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-devtools</artifactId>
		<optional>true</optional>
	</dependency>
</dependencies>

When devtools is running, it detects change when you recompile your application and automatically refreshes it. This works for not only resources but code as well. It also provides a LiveReload server so that it can automatically trigger a browser refresh whenever things change.

Devtools can also be configured to only refresh the browser whenever a static resource has changed (and ignore any change in the code). Just include the following property in your project:

spring.devtools.remote.restart.enabled=false

Prior to devtools, the plugin supported hot refreshing of resources by default which has now be disabled in favour of the solution described above. You can restore it at any time by configuring your project:

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
			<configuration>
				<addResources>true</addResources>
			</configuration>
		</plugin>
	</plugins>
</build>

When addResources is enabled, any src/main/resources directory will be added to the application classpath when you run the application and any duplicate found in target/classes will be removed. This allows hot refreshing of resources which can be very useful when developing web applications. For example, you can work on HTML, CSS or JavaScript files and see your changes immediately without recompiling your application. It is also a helpful way of allowing your front end developers to work without needing to download and install a Java IDE.

A side effect of using this feature is that filtering of resources at build time will not work.

In order to be consistent with the repackage goal, the run goal builds the classpath in such a way that any dependency that is excluded in the plugin’s configuration gets excluded from the classpath as well. For more details, see the dedicated example.

Sometimes it is useful to include test dependencies when running the application. For example, if you want to run your application in a test mode that uses stub classes. If you wish to do this, you can set the useTestClasspath parameter to true.

This is only applied when you run an application: the repackage goal will not add test dependencies to the resulting JAR/WAR.

7.1. spring-boot:run

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Run an application in place.

7.1.1. Required parameters

Name Type Default

classesDirectory

File

${project.build.outputDirectory}

7.1.2. Optional parameters

Name Type Default

addResources

boolean

false

agents

File[]

arguments

String[]

commandlineArguments

String

directories

String[]

environmentVariables

Map

excludeGroupIds

String

excludes

List

folders

String[]

fork

boolean

true

includes

List

jvmArguments

String

mainClass

String

noverify

boolean

optimizedLaunch

boolean

true

profiles

String[]

skip

boolean

false

systemPropertyVariables

Map

useTestClasspath

Boolean

false

workingDirectory

File

7.1.3. Parameter details

addResources

Add maven resources to the classpath directly, this allows live in-place editing of resources. Duplicate resources are removed from target/classes to prevent them to appear twice if ClassLoader.getResources() is called. Please consider adding spring-boot-devtools to your project instead as it provides this feature and many more.

Name

addResources

Type

boolean

Default value

false

User property

spring-boot.run.addResources

Since

1.0.0

agents

Path to agent jars. NOTE: a forked process is required to use this feature.

Name

agents

Type

java.io.File[]

Default value

User property

spring-boot.run.agents

Since

2.2.0

arguments

Arguments that should be passed to the application.

Name

arguments

Type

java.lang.String[]

Default value

User property

Since

1.0.0

classesDirectory

Directory containing the classes and resource files that should be packaged into the archive.

Name

classesDirectory

Type

java.io.File

Default value

${project.build.outputDirectory}

User property

Since

1.0.0

commandlineArguments

Arguments from the command line that should be passed to the application. Use spaces to separate multiple arguments and make sure to wrap multiple values between quotes. When specified, takes precedence over #arguments.

Name

commandlineArguments

Type

java.lang.String

Default value

User property

spring-boot.run.arguments

Since

2.2.3

directories

Additional directories besides the classes directory that should be added to the classpath.

Name

directories

Type

java.lang.String[]

Default value

User property

spring-boot.run.directories

Since

1.0.0

environmentVariables

List of Environment variables that should be associated with the forked process used to run the application. NOTE: a forked process is required to use this feature.

Name

environmentVariables

Type

java.util.Map

Default value

User property

Since

2.1.0

excludeGroupIds

Comma separated list of groupId names to exclude (exact match).

Name

excludeGroupIds

Type

java.lang.String

Default value

User property

spring-boot.excludeGroupIds

Since

1.1.0

excludes

Collection of artifact definitions to exclude. The Exclude element defines mandatory groupId and artifactId properties and an optional classifier property.

Name

excludes

Type

java.util.List

Default value

User property

spring-boot.excludes

Since

1.1.0

folders

Additional directories besides the classes directory that should be added to the classpath.

Name

folders

Type

java.lang.String[]

Default value

User property

spring-boot.run.folders

Since

1.0.0

fork

Flag to indicate if the run processes should be forked. Disabling forking will disable some features such as an agent, custom JVM arguments, devtools or specifying the working directory to use.

Name

fork

Type

boolean

Default value

true

User property

spring-boot.run.fork

Since

1.2.0

includes

Collection of artifact definitions to include. The Include element defines mandatory groupId and artifactId properties and an optional mandatory groupId and artifactId properties and an optional classifier property.

Name

includes

Type

java.util.List

Default value

User property

spring-boot.includes

Since

1.2.0

jvmArguments

JVM arguments that should be associated with the forked process used to run the application. On command line, make sure to wrap multiple values between quotes. NOTE: a forked process is required to use this feature.

Name

jvmArguments

Type

java.lang.String

Default value

User property

spring-boot.run.jvmArguments

Since

1.1.0

mainClass

The name of the main class. If not specified the first compiled class found that contains a 'main' method will be used.

Name

mainClass

Type

java.lang.String

Default value

User property

spring-boot.run.main-class

Since

1.0.0

noverify

Flag to say that the agent requires -noverify.

Name

noverify

Type

boolean

Default value

User property

spring-boot.run.noverify

Since

1.0.0

optimizedLaunch

Whether the JVM’s launch should be optimized.

Name

optimizedLaunch

Type

boolean

Default value

true

User property

spring-boot.run.optimizedLaunch

Since

2.2.0

profiles

The spring profiles to activate. Convenience shortcut of specifying the 'spring.profiles.active' argument. On command line use commas to separate multiple profiles.

Name

profiles

Type

java.lang.String[]

Default value

User property

spring-boot.run.profiles

Since

1.3.0

skip

Skip the execution.

Name

skip

Type

boolean

Default value

false

User property

spring-boot.run.skip

Since

1.3.2

systemPropertyVariables

List of JVM system properties to pass to the process. NOTE: a forked process is required to use this feature.

Name

systemPropertyVariables

Type

java.util.Map

Default value

User property

Since

2.1.0

useTestClasspath

Flag to include the test classpath when running.

Name

useTestClasspath

Type

java.lang.Boolean

Default value

false

User property

spring-boot.run.useTestClasspath

Since

1.3.0

workingDirectory

Current working directory to use for the application. If not specified, basedir will be used. NOTE: a forked process is required to use this feature.

Name

workingDirectory

Type

java.io.File

Default value

User property

spring-boot.run.workingDirectory

Since

1.5.0

7.2. Examples

7.2.1. Debug the Application

By default, the run goal runs your application in a forked process. If you need to debug it, you should add the necessary JVM arguments to enable remote debugging. The following configuration suspend the process until a debugger has joined on port 5005:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<jvmArguments>
						-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005
					</jvmArguments>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

These arguments can be specified on the command line as well, make sure to wrap that properly, that is:

$ mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005"

7.2.2. Using System Properties

System properties can be specified using the systemPropertyVariables attribute. The following example sets property1 to test and property2 to 42:

<project>
	<build>
		<properties>
			<my.value>42</my.value>
		</properties>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<systemPropertyVariables>
						<property1>test</property1>
						<property2>${my.value}</property2>
					</systemPropertyVariables>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

If the value is empty or not defined (i.e. <my-property/>), the system property is set with an empty String as the value. Maven trims values specified in the pom so it is not possible to specify a System property which needs to start or end with a space via this mechanism: consider using jvmArguments instead.

Any String typed Maven variable can be passed as system properties. Any attempt to pass any other Maven variable type (e.g. a List or a URL variable) will cause the variable expression to be passed literally (unevaluated).

The jvmArguments parameter takes precedence over system properties defined with the mechanism above. In the following example, the value for property1 is overridden:

$ mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Dproperty1=overridden"

7.2.3. Using Environment Variables

Environment variables can be specified using the environmentVariables attribute. The following example sets the 'ENV1', 'ENV2', 'ENV3', 'ENV4' env variables:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<environmentVariables>
						<ENV1>5000</ENV1>
						<ENV2>Some Text</ENV2>
						<ENV3/>
						<ENV4></ENV4>
					</environmentVariables>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

If the value is empty or not defined (i.e. <MY_ENV/>), the env variable is set with an empty String as the value. Maven trims values specified in the pom so it is not possible to specify an env variable which needs to start or end with a space.

Any String typed Maven variable can be passed as system properties. Any attempt to pass any other Maven variable type (e.g. a List or a URL variable) will cause the variable expression to be passed literally (unevaluated).

Environment variables defined this way take precedence over existing values.

7.2.4. Using Application Arguments

Application arguments can be specified using the arguments attribute. The following example sets two arguments: property1 and property2=42:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<arguments>
						<argument>property1</argument>
						<argument>property2=${my.value}</argument>
					</arguments>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

On the command-line, arguments are separated by a space the same way jvmArguments are. If an argument contains a space, make sure to quote it. In the following example, two arguments are available: property1 and property2=Hello World:

$ mvn spring-boot:run -Dspring-boot.run.arguments="property1 'property2=Hello World'"

7.2.5. Specify Active Profiles

The active profiles to use for a particular application can be specified using the profiles argument.

The following configuration enables the foo and bar profiles:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<profiles>
						<profile>foo</profile>
						<profile>bar</profile>
					</profiles>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

The profiles to enable can be specified on the command line as well, make sure to separate them with a comma, as shown in the following example:

$ mvn spring-boot:run -Dspring-boot.run.profiles=foo,bar

8. Running Integration Tests

While you may start your Spring Boot application very easily from your test (or test suite) itself, it may be desirable to handle that in the build itself. To make sure that the lifecycle of your Spring Boot application is properly managed around your integration tests, you can use the start and stop goals, as shown in the following example:

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
			<executions>
				<execution>
					<id>pre-integration-test</id>
					<goals>
						<goal>start</goal>
					</goals>
				</execution>
				<execution>
					<id>post-integration-test</id>
					<goals>
						<goal>stop</goal>
					</goals>
				</execution>
			</executions>
		</plugin>
	</plugins>
</build>

Such setup can now use the failsafe-plugin to run your integration tests as you would expect.

By default, the application is started in a separate process and JMX is used to communicate with the application. If you need to configure the JMX port, see the dedicated example.

You could also configure a more advanced setup to skip the integration tests when a specific property has been set, see the dedicated example.

8.1. spring-boot:start

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Start a spring application. Contrary to the run goal, this does not block and allows other goals to operate on the application. This goal is typically used in integration test scenario where the application is started before a test suite and stopped after.

8.1.1. Required parameters

Name Type Default

classesDirectory

File

${project.build.outputDirectory}

8.1.2. Optional parameters

Name Type Default

addResources

boolean

false

agents

File[]

arguments

String[]

commandlineArguments

String

directories

String[]

environmentVariables

Map

excludeGroupIds

String

excludes

List

folders

String[]

fork

boolean

true

includes

List

jmxName

String

jmxPort

int

jvmArguments

String

mainClass

String

maxAttempts

int

noverify

boolean

profiles

String[]

skip

boolean

false

systemPropertyVariables

Map

useTestClasspath

Boolean

false

wait

long

workingDirectory

File

8.1.3. Parameter details

addResources

Add maven resources to the classpath directly, this allows live in-place editing of resources. Duplicate resources are removed from target/classes to prevent them to appear twice if ClassLoader.getResources() is called. Please consider adding spring-boot-devtools to your project instead as it provides this feature and many more.

Name

addResources

Type

boolean

Default value

false

User property

spring-boot.run.addResources

Since

1.0.0

agents

Path to agent jars. NOTE: a forked process is required to use this feature.

Name

agents

Type

java.io.File[]

Default value

User property

spring-boot.run.agents

Since

2.2.0

arguments

Arguments that should be passed to the application.

Name

arguments

Type

java.lang.String[]

Default value

User property

Since

1.0.0

classesDirectory

Directory containing the classes and resource files that should be packaged into the archive.

Name

classesDirectory

Type

java.io.File

Default value

${project.build.outputDirectory}

User property

Since

1.0.0

commandlineArguments

Arguments from the command line that should be passed to the application. Use spaces to separate multiple arguments and make sure to wrap multiple values between quotes. When specified, takes precedence over #arguments.

Name

commandlineArguments

Type

java.lang.String

Default value

User property

spring-boot.run.arguments

Since

2.2.3

directories

Additional directories besides the classes directory that should be added to the classpath.

Name

directories

Type

java.lang.String[]

Default value

User property

spring-boot.run.directories

Since

1.0.0

environmentVariables

List of Environment variables that should be associated with the forked process used to run the application. NOTE: a forked process is required to use this feature.

Name

environmentVariables

Type

java.util.Map

Default value

User property

Since

2.1.0

excludeGroupIds

Comma separated list of groupId names to exclude (exact match).

Name

excludeGroupIds

Type

java.lang.String

Default value

User property

spring-boot.excludeGroupIds

Since

1.1.0

excludes

Collection of artifact definitions to exclude. The Exclude element defines mandatory groupId and artifactId properties and an optional classifier property.

Name

excludes

Type

java.util.List

Default value

User property

spring-boot.excludes

Since

1.1.0

folders

Additional directories besides the classes directory that should be added to the classpath.

Name

folders

Type

java.lang.String[]

Default value

User property

spring-boot.run.folders

Since

1.0.0

fork

Flag to indicate if the run processes should be forked. Disabling forking will disable some features such as an agent, custom JVM arguments, devtools or specifying the working directory to use.

Name

fork

Type

boolean

Default value

true

User property

spring-boot.run.fork

Since

1.2.0

includes

Collection of artifact definitions to include. The Include element defines mandatory groupId and artifactId properties and an optional mandatory groupId and artifactId properties and an optional classifier property.

Name

includes

Type

java.util.List

Default value

User property

spring-boot.includes

Since

1.2.0

jmxName

The JMX name of the automatically deployed MBean managing the lifecycle of the spring application.

Name

jmxName

Type

java.lang.String

Default value

User property

Since

jmxPort

The port to use to expose the platform MBeanServer if the application is forked.

Name

jmxPort

Type

int

Default value

User property

Since

jvmArguments

JVM arguments that should be associated with the forked process used to run the application. On command line, make sure to wrap multiple values between quotes. NOTE: a forked process is required to use this feature.

Name

jvmArguments

Type

java.lang.String

Default value

User property

spring-boot.run.jvmArguments

Since

1.1.0

mainClass

The name of the main class. If not specified the first compiled class found that contains a 'main' method will be used.

Name

mainClass

Type

java.lang.String

Default value

User property

spring-boot.run.main-class

Since

1.0.0

maxAttempts

The maximum number of attempts to check if the spring application is ready. Combined with the "wait" argument, this gives a global timeout value (30 sec by default)

Name

maxAttempts

Type

int

Default value

User property

Since

noverify

Flag to say that the agent requires -noverify.

Name

noverify

Type

boolean

Default value

User property

spring-boot.run.noverify

Since

1.0.0

profiles

The spring profiles to activate. Convenience shortcut of specifying the 'spring.profiles.active' argument. On command line use commas to separate multiple profiles.

Name

profiles

Type

java.lang.String[]

Default value

User property

spring-boot.run.profiles

Since

1.3.0

skip

Skip the execution.

Name

skip

Type

boolean

Default value

false

User property

spring-boot.run.skip

Since

1.3.2

systemPropertyVariables

List of JVM system properties to pass to the process. NOTE: a forked process is required to use this feature.

Name

systemPropertyVariables

Type

java.util.Map

Default value

User property

Since

2.1.0

useTestClasspath

Flag to include the test classpath when running.

Name

useTestClasspath

Type

java.lang.Boolean

Default value

false

User property

spring-boot.run.useTestClasspath

Since

1.3.0

wait

The number of milli-seconds to wait between each attempt to check if the spring application is ready.

Name

wait

Type

long

Default value

User property

Since

workingDirectory

Current working directory to use for the application. If not specified, basedir will be used. NOTE: a forked process is required to use this feature.

Name

workingDirectory

Type

java.io.File

Default value

User property

spring-boot.run.workingDirectory

Since

1.5.0

8.2. spring-boot:stop

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Stop an application that has been started by the "start" goal. Typically invoked once a test suite has completed.

8.2.1. Optional parameters

Name Type Default

fork

Boolean

jmxName

String

jmxPort

int

skip

boolean

false

8.2.2. Parameter details

fork

Flag to indicate if process to stop was forked. By default, the value is inherited from the MavenProject. If it is set, it must match the value used to StartMojo start the process.

Name

fork

Type

java.lang.Boolean

Default value

User property

spring-boot.stop.fork

Since

1.3.0

jmxName

The JMX name of the automatically deployed MBean managing the lifecycle of the application.

Name

jmxName

Type

java.lang.String

Default value

User property

Since

jmxPort

The port to use to lookup the platform MBeanServer if the application has been forked.

Name

jmxPort

Type

int

Default value

User property

Since

skip

Skip the execution.

Name

skip

Type

boolean

Default value

false

User property

spring-boot.stop.skip

Since

1.3.2

8.3. Examples

8.3.1. Random Port for Integration Tests

One nice feature of the Spring Boot test integration is that it can allocate a free port for the web application. When the start goal of the plugin is used, the Spring Boot application is started separately, making it difficult to pass the actual port to the integration test itself.

The example below showcases how you could achieve the same feature using the Build Helper Maven Plugin:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.codehaus.mojo</groupId>
				<artifactId>build-helper-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>reserve-tomcat-port</id>
						<goals>
							<goal>reserve-network-port</goal>
						</goals>
						<phase>process-resources</phase>
						<configuration>
							<portNames>
								<portName>tomcat.http.port</portName>
							</portNames>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>pre-integration-test</id>
						<goals>
							<goal>start</goal>
						</goals>
						<configuration>
							<arguments>
								<argument>--server.port=${tomcat.http.port}</argument>
							</arguments>
						</configuration>
					</execution>
					<execution>
						<id>post-integration-test</id>
						<goals>
							<goal>stop</goal>
						</goals>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-failsafe-plugin</artifactId>
				<configuration>
					<systemPropertyVariables>
						<test.server.port>${tomcat.http.port}</test.server.port>
					</systemPropertyVariables>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

You can now retrieve the test.server.port system property in any of your integration test to create a proper URL to the server.

8.3.2. Customize JMX port

The jmxPort property allows to customize the port the plugin uses to communicate with the Spring Boot application.

This example shows how you can customize the port in case 9001 is already used:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
                   <configuration>
					<jmxPort>9009</jmxPort>
				</configuration>
				<executions>
					<execution>
						<id>pre-integration-test</id>
						<goals>
							<goal>start</goal>
						</goals>
					</execution>
					<execution>
						<id>post-integration-test</id>
						<goals>
							<goal>stop</goal>
						</goals>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>
If you need to configure the JMX port, make sure to do so in the global configuration as shown above so that it is shared by both goals.

8.3.3. Skip Integration Tests

The skip property allows to skip the execution of the Spring Boot maven plugin altogether.

This example shows how you can skip integration tests with a command-line property and still make sure that the repackage goal runs:

<project>
	<properties>
		<skip.it>false</skip.it>
	</properties>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<id>pre-integration-test</id>
						<goals>
							<goal>start</goal>
						</goals>
						<configuration>
							<skip>${skip.it}</skip>
						</configuration>
					</execution>
					<execution>
						<id>post-integration-test</id>
						<goals>
							<goal>stop</goal>
						</goals>
						<configuration>
							<skip>${skip.it}</skip>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-failsafe-plugin</artifactId>
				<configuration>
					<skip>${skip.it}</skip>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

By default, the integration tests will run but this setup allows you to easily disable them on the command-line as follows:

$ mvn verify -Dskip.it=true

9. Integrating with Actuator

Spring Boot Actuator displays build-related information if a META-INF/build-info.properties file is present. The build-info goal generates such file with the coordinates of the project and the build time. It also allows you to add an arbitrary number of additional properties, as shown in the following example:

<project>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<executions>
					<execution>
						<goals>
							<goal>build-info</goal>
						</goals>
						<configuration>
							<additionalProperties>
								<encoding.source>UTF-8</encoding.source>
								<encoding.reporting>UTF-8</encoding.reporting>
								<java.source>${maven.compiler.source}</java.source>
								<java.target>${maven.compiler.target}</java.target>
							</additionalProperties>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

This configuration will generate a build-info.properties at the expected location with four additional keys.

maven.compiler.source and maven.compiler.target are expected to be regular properties available in the project. They will be interpolated as you would expect.

9.1. spring-boot:build-info

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Generate a build-info.properties file based the content of the current MavenProject.

9.1.1. Optional parameters

Name Type Default

additionalProperties

Map

outputFile

File

${project.build.outputDirectory}/META-INF/build-info.properties

time

String

9.1.2. Parameter details

additionalProperties

Additional properties to store in the build-info.properties file. Each entry is prefixed by build. in the generated build-info.properties.

Name

additionalProperties

Type

java.util.Map

Default value

User property

Since

outputFile

The location of the generated build-info.properties file.

Name

outputFile

Type

java.io.File

Default value

${project.build.outputDirectory}/META-INF/build-info.properties

User property

Since

time

The value used for the build.time property in a form suitable for Instant#parse(CharSequence). Defaults to session.request.startTime. To disable the build.time property entirely, use 'off'.

Name

time

Type

java.lang.String

Default value

User property

Since

2.2.0

10. Help Information

The help goal is a standard goal that displays information on the capabilities of the plugin.

10.1. spring-boot:help

org.springframework.boot:spring-boot-maven-plugin:2.4.0-SNAPSHOT

Display help information on spring-boot-maven-plugin. Call mvn spring-boot:help -Ddetail=true -Dgoal=<goal-name> to display parameter details.

10.1.1. Optional parameters

Name Type Default

detail

boolean

false

goal

String

indentSize

int

2

lineLength

int

80

10.1.2. Parameter details

detail

If true, display all settable properties for each goal.

Name

detail

Type

boolean

Default value

false

User property

detail

Since

goal

The name of the goal for which to show help. If unspecified, all goals will be displayed.

Name

goal

Type

java.lang.String

Default value

User property

goal

Since

indentSize

The number of spaces per indentation level, should be positive.

Name

indentSize

Type

int

Default value

2

User property

indentSize

Since

lineLength

The maximum length of a display line, should be positive.

Name

lineLength

Type

int

Default value

80

User property

lineLength

Since