Earlier on, Spring migrated from a monolithic approach - the whole framework, to a modular one - bean, context, test, etc. so that one could decide to use only the required modules. This modularity came at a cost, however: in the Maven build configuration (or the Gradle one for that matter), one had to specify the version for each used module.
<?xml version="1.0" encoding="UTF-8"?>
<project...>
...
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.0.5.RELEASE</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>Of course, professional Maven users would improve this POM with the following:
<?xml version="1.0" encoding="UTF-8"?>
<project...>
...
<properties>
<spring.version>4.0.5.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>There’s an more concise way to achieve the same through a BOM typed POM (see section on scope import) since version 3.2.6 though.
<?xml version="1.0" encoding="UTF-8"?>
<project...>
...
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-framework-bom</artifactId>
<type>pom</type>
<version>4.0.5.RELEASE</version>
<scope>import</scope>
</dependency>
<dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>Note that Spring’s BOM only sets version but not scope, this has to be done in each user POM.
Spring released very recently the Spring IO platform which also includes a BOM. This BOM not only includes Spring dependencies but also other third-party libraries.
<?xml version="1.0" encoding="UTF-8"?>
<project...>
...
<dependencyManagement>
<dependencies>
<dependency>
<groupId>io.spring.platform</groupId>
<artifactId>platform-bom</artifactId>
<type>pom</type>
<version>1.0.0.RELEASE</version>
<scope>import</scope>
</dependency>
<dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.testng</groupId>
<artifactId>testng</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>There’s one single problem with Spring IO platform’s BOM, there’s no simple mapping from the BOM version to declared dependencies versions. For example, the BOM’s 1.0.0.RELEASE maps to Spring 4.0.5.RELEASE.