Gradleを使用した実行可能JARの構築

build.gradleでは次のように構成されています.

apply plugin: 'java'
apply plugin: 'idea'

jar {
    String someString = ''
    configurations.runtime.each {
        someString = someString + "lib/" + it.name + " ";
    }
    manifest {
        attributes 'Main-Class': 'xxx'//               
        attributes 'Class-Path': someString
    }
}

//           
task clearPj(type: Delete) {
    delete 'build', 'target'
}
// JAR       
task release(type: Copy, dependsOn: [build]) {
    from configurations.runtime
    into 'build/libs/lib'
}