Spring-boot-starter-parent Example

In this spring boot tutorial, we will learn about spring-boot-starter-parent dependency which is used internally by all spring boot dependencies. We will also learn what all configurations this dependency provides, and how to override them.

What is spring-boot-starter-parent dependency?

The spring-boot-starter-parent dependency is the parent POM providing dependency and plugin management for Spring Boot-based applications. It contains the default versions of Java to use, the default versions of dependencies that Spring Boot uses, and the default configuration of the Maven plugins.

Few important configurations provided by this file are as below. Please refer to this link to read the complete configuration.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd;
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-dependencies</artifactId>
		<version>${revision}</version>
		<relativePath>../../spring-boot-dependencies</relativePath>
	</parent>
	<artifactId>spring-boot-starter-parent</artifactId>
	<packaging>pom</packaging>
	<name>Spring Boot Starter Parent</name>
	<description>Parent pom providing dependency and plugin management for applications
		built with Maven</description>
	<properties>
		<java.version>1.8</java.version>
		<resource.delimiter>@</resource.delimiter> <!-- delimiter that doesn't clash with Spring ${} placeholders -->
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<maven.compiler.source>${java.version}</maven.compiler.source>
		<maven.compiler.target>${java.version}</maven.compiler.target>
	</properties>
	
	...

	<resource>
		<directory>${basedir}/src/main/resources</directory>
		<filtering>true</filtering>
		<includes>
			<include>**/application*.yml</include>
			<include>**/application*.yaml</include>
			<include>**/application*.properties</include>
		</includes>
	</resource>

</project>

The spring-boot-starter-parent dependency further inherits from spring-boot-dependencies, which is defined at the top of above POM file at line number : 9.

This file is the actual file which contains the information of default version to use for all libraries. The following code shows the different versions of various dependencies that are configured in spring-boot-dependencies:

<properties>
	<!-- Dependency versions -->
	<activemq.version>5.15.3</activemq.version>
	<antlr2.version>2.7.7</antlr2.version>
	<appengine-sdk.version>1.9.63</appengine-sdk.version>
	<artemis.version>2.4.0</artemis.version>
	<aspectj.version>1.8.13</aspectj.version>
	<assertj.version>3.9.1</assertj.version>
	<atomikos.version>4.0.6</atomikos.version>
	<bitronix.version>2.1.4</bitronix.version>
	<byte-buddy.version>1.7.11</byte-buddy.version>
	<caffeine.version>2.6.2</caffeine.version>
	<cassandra-driver.version>3.4.0</cassandra-driver.version>
	<classmate.version>1.3.4</classmate.version>

	...
	...
</properties>

Above list is very long and you can read complete list in this link.

How to override default dependency version?

As you see, spring boot has default version to use for most of dependencies. You can override the version of your choice or project need, in properties tag in your project’s pom.xml file.

e.g. Spring boot used default version of google GSON library as 2.8.2.

<groovy.version>2.4.14</groovy.version>
<gson.version>2.8.2</gson.version>
<h2.version>1.4.197</h2.version>

I want to use 2.7 of gson dependency. So I will give this information in properties tag like this.

<properties>
	<java.version>1.8</java.version>
	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	<gson.version>2.7</gson.version>
</properties>

Now in your eclipse editor, you can see the message as : The managed version is 2.7 The artifact is managed in org.springframework.boot:spring-boot-dependencies:2.0.0.RELEASE.

Drop me your questions in comments section.

Happy Learning !!