Unable to initialize POM pom-default.xml: Failed to validate POM for project com.izeye:samples-spring-boot-branches at /Users/izeye/IdeaProjects/samples-spring-boot-branches/build/publications/maven/pom-default.xml

When you use Spring Boot with Gradle and run the 'publishMavenPublicationToMavenLocal' task,

you can encounter the following error:

* What went wrong:
Execution failed for task ':publishMavenPublicationToMavenLocal'.
> Failed to publish publication 'maven' to repository 'MavenLocal'
   > Unable to initialize POM pom-default.xml: Failed to validate POM for project com.izeye:samples-spring-boot-branches at /Users/izeye/IdeaProjects/samples-spring-boot-branches/build/publications/maven/pom-default.xml

It's caused by absence of versions of artifacts provided by 'spring-boot' plugin.

You can use the dependency management plugin as follows:

buildscript {
    repositories {
        jcenter()
        maven { url "http://repo.spring.io/snapshot" }
        maven { url "http://repo.spring.io/libs-milestone" }
        maven { url "http://repo.spring.io/libs-release" }
        mavenLocal()
    }

    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.2.2.RELEASE")

        classpath("io.spring.gradle:dependency-management-plugin:0.4.0.RELEASE")
    }
}

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

dependencyManagement {
    imports {
        mavenBom 'org.springframework.boot:spring-boot-dependencies:1.2.2.RELEASE'
    }
}

Reference:
https://github.com/spring-gradle-plugins/dependency-management-plugin