13. Build Systems

13. Build Systems
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It is strongly recommended that you choose a build system that supports dependency management and that can consume artifacts published to the “Maven Central” repository. We would recommend that you choose Maven or Gradle. It is possible to get Spring Boot to work with other build systems (Ant, for example), but they are not particularly well supported.

13.1 Dependency Management

Each release of Spring Boot provides a curated list of dependencies that it supports. In practice, you do not need to provide a version for any of these dependencies in your build configuration, as Spring Boot manages that for you. When you upgrade Spring Boot itself, these dependencies are upgraded as well in a consistent way.

	Note
	You can still specify a version and override Spring Boot’s recommendations if you need to do so.

The curated list contains all the spring modules that you can use with Spring Boot as well as a refined list of third party libraries. The list is available as a standard Bills of Materials (spring-boot-dependencies) that can be used with both Maven and Gradle.

	Warning
	Each release of Spring Boot is associated with a base version of the Spring Framework. We highly recommend that you not specify its version.

13.2 Maven

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.
Sensible resource filtering.
Sensible plugin configuration (exec plugin, 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)

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

13.2.1 Inheriting the Starter Parent

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>2.0.0.RELEASE</version>
</parent>

	Note
	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 upgrade to another Spring Data release train, you would add the following to your pom.xml:

<properties>
	<spring-data-releasetrain.version>Fowler-SR2</spring-data-releasetrain.version>
</properties>

	Tip
	Check the `spring-boot-dependencies` pom for a list of supported properties.

13.2.2 Using Spring Boot without the Parent POM

Not everyone likes inheriting 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 a scope=import dependency, as follows:

<dependencyManagement>
		<dependencies>
		<dependency>
			<!-- Import dependency management from Spring Boot -->
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-dependencies</artifactId>
			<version>2.0.0.RELEASE</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
	</dependencies>
</dependencyManagement>

The preceding sample setup does not let you override individual dependencies by using a property, as explained above. To achieve the same result, you need to add an entry in the dependencyManagement of your project before the spring-boot-dependencies entry. For instance, to upgrade to another Spring Data release train, you could add the following element to your pom.xml:

<dependencyManagement>
	<dependencies>
		<!-- Override Spring Data release train provided by Spring Boot -->
		<dependency>
			<groupId>org.springframework.data</groupId>
			<artifactId>spring-data-releasetrain</artifactId>
			<version>Fowler-SR2</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-dependencies</artifactId>
			<version>2.0.0.RELEASE</version>
			<type>pom</type>
			<scope>import</scope>
		</dependency>
	</dependencies>
</dependencyManagement>

	Note
	In the preceding example, we specify a BOM, but any dependency type can be overridden in the same way.

13.2.3 Using the Spring Boot Maven Plugin

Spring Boot includes a Maven plugin that can package the project as an executable jar. Add the plugin to your <plugins> section if you want to use it, as shown in the following example:

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

	Note
	If you use the Spring Boot starter parent pom, you need to add only the plugin. There is no need to configure it unless you want to change the settings defined in the parent.

13.3 Gradle

To learn about using Spring Boot with Gradle, please refer to the documentation for Spring Boot’s Gradle plugin:

Reference (HTML and PDF)
API

13.4 Ant

It is possible to build a Spring Boot project using Apache Ant+Ivy. The spring-boot-antlib “AntLib” module is also available to help Ant create executable jars.

To declare dependencies, a typical ivy.xml file looks something like the following example:

<ivy-module version="2.0">
	<info organisation="org.springframework.boot" module="spring-boot-sample-ant" />
	<configurations>
		<conf name="compile" description="everything needed to compile this module" />
		<conf name="runtime" extends="compile" description="everything needed to run this module" />
	</configurations>
	<dependencies>
		<dependency org="org.springframework.boot" name="spring-boot-starter"
			rev="${spring-boot.version}" conf="compile" />
	</dependencies>
</ivy-module>

A typical build.xml looks like the following example:

<project
	xmlns:ivy="antlib:org.apache.ivy.ant"
	xmlns:spring-boot="antlib:org.springframework.boot.ant"
	name="myapp" default="build">

	<property name="spring-boot.version" value="2.0.0.RELEASE" />

	<target name="resolve" description="--> retrieve dependencies with ivy">
		<ivy:retrieve pattern="lib/[conf]/[artifact]-[type]-[revision].[ext]" />
	</target>

	<target name="classpaths" depends="resolve">
		<path id="compile.classpath">
			<fileset dir="lib/compile" includes="*.jar" />
		</path>
	</target>

	<target name="init" depends="classpaths">
		<mkdir dir="build/classes" />
	</target>

	<target name="compile" depends="init" description="compile">
		<javac srcdir="src/main/java" destdir="build/classes" classpathref="compile.classpath" />
	</target>

	<target name="build" depends="compile">
		<spring-boot:exejar destfile="build/myapp.jar" classes="build/classes">
			<spring-boot:lib>
				<fileset dir="lib/runtime" />
			</spring-boot:lib>
		</spring-boot:exejar>
	</target>
</project>

	Tip
	If you do not want to use the `spring-boot-antlib` module, see the Section 86.9, “Build an Executable Archive from Ant without Using `spring-boot-antlib`” “How-to” .

13.5 Starters

Starters are a set of convenient dependency descriptors that you can include in your application. You get a one-stop shop for all the Spring and related technologies that you need without having to hunt through sample code and copy-paste loads of dependency descriptors. For example, if you want to get started using Spring and JPA for database access, include the spring-boot-starter-data-jpa dependency in your project.

The starters contain a lot of the dependencies that you need to get a project up and running quickly and with a consistent, supported set of managed transitive dependencies.

What’s in a name

All official starters follow a similar naming pattern; spring-boot-starter-*, where * is a particular type of application. This naming structure is intended to help when you need to find a starter. The Maven integration in many IDEs lets you search dependencies by name. For example, with the appropriate Eclipse or STS plugin installed, you can press ctrl-space in the POM editor and type “spring-boot-starter” for a complete list.

As explained in the “Creating Your Own Starter” section, third party starters should not start with spring-boot, as it is reserved for official Spring Boot artifacts. Rather, a third-party starter typically starts with the name of the project. For example, a third-party starter project called thirdpartyproject would typically be named thirdpartyproject-spring-boot-starter.

The following application starters are provided by Spring Boot under the org.springframework.boot group:

Table 13.1. Spring Boot application starters

Name	Description	Pom
`spring-boot-starter`	Core starter, including auto-configuration support, logging and YAML	Pom
`spring-boot-starter-activemq`	Starter for JMS messaging using Apache ActiveMQ	Pom
`spring-boot-starter-amqp`	Starter for using Spring AMQP and Rabbit MQ	Pom
`spring-boot-starter-aop`	Starter for aspect-oriented programming with Spring AOP and AspectJ	Pom
`spring-boot-starter-artemis`	Starter for JMS messaging using Apache Artemis	Pom
`spring-boot-starter-batch`	Starter for using Spring Batch	Pom
`spring-boot-starter-cache`	Starter for using Spring Framework’s caching support	Pom
`spring-boot-starter-cloud-connectors`	Starter for using Spring Cloud Connectors which simplifies connecting to services in cloud platforms like Cloud Foundry and Heroku	Pom
`spring-boot-starter-data-cassandra`	Starter for using Cassandra distributed database and Spring Data Cassandra	Pom
`spring-boot-starter-data-cassandra-reactive`	Starter for using Cassandra distributed database and Spring Data Cassandra Reactive	Pom
`spring-boot-starter-data-couchbase`	Starter for using Couchbase document-oriented database and Spring Data Couchbase	Pom
`spring-boot-starter-data-couchbase-reactive`	Starter for using Couchbase document-oriented database and Spring Data Couchbase Reactive	Pom
`spring-boot-starter-data-elasticsearch`	Starter for using Elasticsearch search and analytics engine and Spring Data Elasticsearch	Pom
`spring-boot-starter-data-jpa`	Starter for using Spring Data JPA with Hibernate	Pom
`spring-boot-starter-data-ldap`	Starter for using Spring Data LDAP	Pom
`spring-boot-starter-data-mongodb`	Starter for using MongoDB document-oriented database and Spring Data MongoDB	Pom
`spring-boot-starter-data-mongodb-reactive`	Starter for using MongoDB document-oriented database and Spring Data MongoDB Reactive	Pom
`spring-boot-starter-data-neo4j`	Starter for using Neo4j graph database and Spring Data Neo4j	Pom
`spring-boot-starter-data-redis`	Starter for using Redis key-value data store with Spring Data Redis and the Lettuce client	Pom
`spring-boot-starter-data-redis-reactive`	Starter for using Redis key-value data store with Spring Data Redis reactive and the Lettuce client	Pom
`spring-boot-starter-data-rest`	Starter for exposing Spring Data repositories over REST using Spring Data REST	Pom
`spring-boot-starter-data-solr`	Starter for using the Apache Solr search platform with Spring Data Solr	Pom
`spring-boot-starter-freemarker`	Starter for building MVC web applications using FreeMarker views	Pom
`spring-boot-starter-groovy-templates`	Starter for building MVC web applications using Groovy Templates views	Pom
`spring-boot-starter-hateoas`	Starter for building hypermedia-based RESTful web application with Spring MVC and Spring HATEOAS	Pom
`spring-boot-starter-integration`	Starter for using Spring Integration	Pom
`spring-boot-starter-jdbc`	Starter for using JDBC with the Tomcat JDBC connection pool	Pom
`spring-boot-starter-jersey`	Starter for building RESTful web applications using JAX-RS and Jersey. An alternative to `spring-boot-starter-web`	Pom
`spring-boot-starter-jooq`	Starter for using jOOQ to access SQL databases. An alternative to `spring-boot-starter-data-jpa` or `spring-boot-starter-jdbc`	Pom
`spring-boot-starter-json`	Starter for reading and writing json	Pom
`spring-boot-starter-jta-atomikos`	Starter for JTA transactions using Atomikos	Pom
`spring-boot-starter-jta-bitronix`	Starter for JTA transactions using Bitronix	Pom
`spring-boot-starter-jta-narayana`	Spring Boot Narayana JTA Starter	Pom
`spring-boot-starter-mail`	Starter for using Java Mail and Spring Framework’s email sending support	Pom
`spring-boot-starter-mustache`	Starter for building web applications using Mustache views	Pom
`spring-boot-starter-quartz`	Spring Boot Quartz Starter	Pom
`spring-boot-starter-security`	Starter for using Spring Security	Pom
`spring-boot-starter-test`	Starter for testing Spring Boot applications with libraries including JUnit, Hamcrest and Mockito	Pom
`spring-boot-starter-thymeleaf`	Starter for building MVC web applications using Thymeleaf views	Pom
`spring-boot-starter-validation`	Starter for using Java Bean Validation with Hibernate Validator	Pom
`spring-boot-starter-web`	Starter for building web, including RESTful, applications using Spring MVC. Uses Tomcat as the default embedded container	Pom
`spring-boot-starter-web-services`	Starter for using Spring Web Services	Pom
`spring-boot-starter-webflux`	Starter for building WebFlux applications using Spring Framework’s Reactive Web support	Pom
`spring-boot-starter-websocket`	Starter for building WebSocket applications using Spring Framework’s WebSocket support	Pom

In addition to the application starters, the following starters can be used to add production ready features:

Table 13.2. Spring Boot production starters

Name	Description	Pom
`spring-boot-starter-actuator`	Starter for using Spring Boot’s Actuator which provides production ready features to help you monitor and manage your application	Pom

Finally, Spring Boot also includes the following starters that can be used if you want to exclude or swap specific technical facets:

Table 13.3. Spring Boot technical starters

Name	Description	Pom
`spring-boot-starter-jetty`	Starter for using Jetty as the embedded servlet container. An alternative to `spring-boot-starter-tomcat`	Pom
`spring-boot-starter-log4j2`	Starter for using Log4j2 for logging. An alternative to `spring-boot-starter-logging`	Pom
`spring-boot-starter-logging`	Starter for logging using Logback. Default logging starter	Pom
`spring-boot-starter-reactor-netty`	Starter for using Reactor Netty as the embedded reactive HTTP server.	Pom
`spring-boot-starter-tomcat`	Starter for using Tomcat as the embedded servlet container. Default servlet container starter used by `spring-boot-starter-web`	Pom
`spring-boot-starter-undertow`	Starter for using Undertow as the embedded servlet container. An alternative to `spring-boot-starter-tomcat`	Pom

	Tip
	For a list of additional community contributed starters, see the README file in the `spring-boot-starters` module on GitHub.