If you open a Spring Boot project, you will see that at the top they all use a spring-boot-starter-parent as the parent in pom.xml.
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.0.RELEASE</version> <relativePath/> </parent>Parent Poms allow you to manage several aspects for the child projects such as:
- Dependency Management – Version of dependencies
- Configuration – Java Version and Other Properties
- Default Plugin Configuration
A look inside Spring Boot Starter Parent
Spring Boot Starter Parent defines spring-boot-dependencies as the parent pom. It inherits dependency management from spring-boot-dependencies. Details in the next section.
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>${revision}</version> <relativePath>../../spring-boot-dependencies</relativePath> </parent>The Parent pom goes on defining a list of properties such as:
<properties> <main.basedir>${basedir}/../../..</main.basedir> <java.version>1.8</java.version> <resource.delimiter>@</resource.delimiter> <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>A project can override this by specifying again the property, for example:
<java.version>1.9</java.version> How to override default dependency version?
The actual version for all dependencies is stored in the spring-boot-project/spring-boot-dependencies/pom.xml. Here is an excerpt of it:
<properties> <activemq.version>5.15.7</activemq.version> <antlr2.version>2.7.7</antlr2.version> <appengine-sdk.version>1.9.67</appengine-sdk.version> <artemis.version>2.6.3</artemis.version> <aspectj.version>1.9.2</aspectj.version> <assertj.version>3.11.1</assertj.version> <atomikos.version>4.0.6</atomikos.version> <bitronix.version>2.1.4</bitronix.version> <byte-buddy.version>1.9.3</byte-buddy.version> <caffeine.version>2.6.2</caffeine.version> <cassandra-driver.version>3.6.0</cassandra-driver.version> <classmate.version>1.4.0</classmate.version> <commons-codec.version>1.11</commons-codec.version> <commons-dbcp2.version>2.5.0</commons-dbcp2.version> <commons-lang3.version>3.8.1</commons-lang3.version> <commons-pool.version>1.6</commons-pool.version>Therefore, if you wanted to override the default version of a dependency, you can just provide this information in properties tag like this:
<properties> <activemq.version>5.15.1</activemq.version> </properties>
