执行gradle build一直报错 ?报错

一直报错 multi-project-build:core:unspecified

跟项目配置文件：
build.gradle
subprojects {
apply plugin: 'java'
apply plugin: 'eclipse'

repositories {
    mavenCentral()
}

}
settings.gradle

include 'app'
include 'core'

子项目app的：
apply plugin: 'application'

dependencies {
compile 'log4j:log4j:1.2.17'
compile project(':core')
}

mainClassName = 'net.petrikainulainen.gradle.client.HelloWorld'

task copyLicense {
outputs.file new File("$buildDir/LICENSE")
doLast {
copy {
from "LICENSE"
into "$buildDir"
}
}
}

applicationDistribution.from(copyLicense) {
into ""
}

子项目core的：
repositories {
mavenCentral()
}

dependencies {
compile("org.springframework.boot:spring-boot-starter-jdbc")
testCompile 'junit:junit:4.11'
}