gradle中的系统类型依赖是什么意思？

Question

要将maven项目转换为Gradle，我在项目上运行gradle init。结果build.gradle（下面的代码段）将所有本地依赖项转换为system，但似乎没有关于此类依赖性的大量信息。有谁熟悉这些Gradle依赖项？

...
dependencies {
    compile group: 'org.hamcrest', name: 'hamcrest-core', version:'1.3'
    compile group: 'org.restlet.jse', name: 'org.restlet', version:'2.3.7'
    compile group: 'org.restlet.jse', name: 'org.restlet.ext.jackson', version:'2.3.7'
    compile group: 'joda-time', name: 'joda-time', version:'2.7'
    testCompile group: 'org.mockito', name: 'mockito-all', version:'1.10.19'
    testCompile group: 'org.powermock', name: 'powermock-module-junit4', version:'1.6.5'
    testCompile group: 'org.powermock', name: 'powermock-api-mockito', version:'1.6.5'
    testCompile group: 'junit', name: 'junit', version:'4.11'
    system group: '...', name: '...', version:'1.0-SNAPSHOT'
    system group: '...', name: '...', version:'1.0-SNAPSHOT'
}