：在Gradle（混合Java + Kotlin项目）中compileKotlin失败

我有一个混合Java / Kotlin项目与以下结构：

我建立它的Gradle脚本如下所示：

buildscript { ext.kotlin_version = '1.0.4' repositories { mavenCentral() } dependencies { classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" } } apply plugin: "kotlin" apply plugin: "application" mainClassName = "com.mycopany.App" sourceSets { deploy } repositories { mavenCentral() } dependencies { compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version" testCompile 'junit:junit:4.11' testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version" } test.testClassesDir = project.tasks.compileTestKotlin.destinationDir task wrapper(type: Wrapper) { gradleVersion="2.7" } 

App.kt是一个简单的程序：

 package com.mycompany.App class App { fun run() { System.out.println("Hello, Kotlin world!") } } fun main(args : Array<String>) { val app = App() app.run() } 

当我尝试使用gradle build构建它时，出现以下错误消息：

16:13:16.768 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':copyMainKotlinClasses' 16:13:16.768 [LIFECYCLE] [class org.gradle.TaskExecutionLogger] :copyMainKotlinClasses FAILED 16:13:16.769 [INFO] [org.gradle.execution.taskgraph.AbstractTaskPlanExecutor] :copyMainKotlinClasses (Thread[main,5,main]) completed. Took 0.042 secs. 16:13:16.770 [DEBUG] [org.gradle.execution.taskgraph.AbstractTaskPlanExecutor] Task worker [Thread[main,5,main]] finished, busy: 0.28 secs, idle: 0.005 secs 16:13:16.827 [LIFECYCLE] [org.gradle.BuildResultLogger] 16:13:16.828 [LIFECYCLE] [org.gradle.BuildResultLogger] BUILD FAILED 16:13:16.829 [LIFECYCLE] [org.gradle.BuildResultLogger]

我得到了同样的错误，当我尝试在Eclipse（也与Gradle）中构建它。

如果我用--stacktrace选项运行相同的脚本，我得到这个：

Caused by: java.lang.NullPointerException at org.gradle.util.GFileUtils.mkdirs(GFileUtils.java:265) at org.gradle.api.internal.project.taskfactory.OutputFilePropertyAnnotat ionHandler$2$1.execute(OutputFilePropertyAnnotationHandler.java:73) at org.gradle.api.internal.project.taskfactory.OutputFilePropertyAnnotat ionHandler$2$1.execute(OutputFilePropertyAnnotationHandler.java:68) at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(Abstra ctTask.java:621) at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(Abstra ctTask.java:604) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.ex ecuteAction(ExecuteActionsTaskExecuter.java:80) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.ex ecuteActions(ExecuteActionsTaskExecuter.java:61) ... 57 more

我该如何解决这个问题？