Código

buildscript {
  repositories {
    jcenter()
  }
  dependencies { 
   classpath 'org.springframework.boot:spring-boot-gradle-plugin:1.2.0.RELEASE'
  }
}
apply plugin: 'spring-boot'
repositories { 
  jcenter()
}
dependencies {
  compile "org.springframework.boot:spring-boot-starter-actuator"
  compile "org.springframework.boot:spring-boot-starter-web"
}

Script de montagem do Gradle.

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@EnableAutoConfiguration
public class Main {
    public static void main(String[] args) {
        SpringApplication.run(Main.class);
    }
}