In Gradle, how do I declare common dependencies in a single place?

Question

In Maven there is a very useful feature when you can define a dependency in the section of the parent POM, and reference that depen

Answer 1

io.spring.gradle:dependency-management-plugin plugin has problems with new Gradle 3.x series but stable for 2.x series. For reference look to bug report Drop support for Gradle 3 #115

In case of Spring (main promoter of BOM usage) you may end with:

buildscript {
    repositories {
        mavenLocal()
        jcenter()
    }
    dependencies {
        classpath 'io.spring.gradle:dependency-management-plugin:1.0.0.RELEASE'
    }
}

repositories {
    mavenLocal()
    jcenter()
}

apply plugin: 'java'
apply plugin: 'io.spring.dependency-management'

dependencyManagement {
    imports {
        mavenBom 'io.spring.platform:platform-bom:Athens-SR3'
    }
}

dependencies {
    compile 'org.springframework.boot:spring-boot-starter-web'

    testCompile 'org.springframework.boot:spring-boot-starter-test'
}

Note that io.spring.platform:platform-bom have org.springframework.boot:spring-boot-starter-parent as parent so it is compatable with Spring Boot

You can verify actual dependency resolution via:

$ gradle dependencies
$ gradle dependencies --configuration compile
$ gradle dependencies -p $SUBPROJ

$ gradle buildEnvironment
$ gradle buildEnvironment -p $SUBPROJ

or with task:

task showMeCache {
    configurations.compile.each { println it }
}

Read official Soring blog post Better dependency management for Gradle to understand the reason of introducing io.spring.gradle:dependency-management-plugin.