问在AppEngine上使用Java执行器导致AccessControlException

EN

如何让java.util.concurrent.Executor或CompletionService在谷歌AppEngine上工作？类都是正式白名单，但是在尝试提交异步任务时，我会得到一个运行时安全错误。

代码：

    // uses the async API but this factory makes it so that tasks really
    // happen sequentially
    Executor executor = java.util.concurrent.Executors.newSingleThreadExecutor();
    // wrap Executor in CompletionService
    CompletionService<String> completionService = 
        new ExecutorCompletionService<String>(executor);
    final SomeTask someTask = new SomeTask();
    // this line throws exception
    completionService.submit(new Callable<String>(){
        public String call() {
            return someTask.doNothing("blah");
        }
    });
    // alternately, send Runnable task directly to Executor,
    // which also throws an exception
    executor.execute(new Runnable(){
        public void run() {
            someTask.doNothing("blah");
        }
    });
}

private class SomeTask{
    public String doNothing(String message){
        return message;
    }
}

例外：

java.security.AccessControlContext.checkPermission(AccessControlContext.java:323) at java.security.AccessController.checkPermission(AccessController.java:546) at java.lang.SecurityManager.checkPermission(SecurityManager.java:532) at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166) at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkAccess(DevAppServerFactory.java:191在java.lang.ThreadGroup.checkAccess(ThreadGroup.java:288) at java.lang.Thread.init(Thread.java:332) at java.lang.Thread.(Thread.java:565) at java.util.concurrent.Executors$DefaultThreadFactory.newThread(Executors.java:542) at java.util.concurrent.ThreadPoolExecutor.addThread(ThreadPoolExecutor.java:672) at java.util.concurrent.ThreadPoolExecutor.addIfUnderCorePoolSize(ThreadPoolExecutor.java:697) at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:652) at java.util.concurrent.Executors$DelegatedExecutorService.execute(Executors.java:590) at java.util.concurrent.ExecutorCompletionService.submit(ExecutorCompletionService.java:152)

这段代码在Tomcat上或通过命令行JVM运行时运行良好。但是，它在Eclipse容器(尝试使用AppEngine插件和maven-gae)中会产生瓶颈。

AppEngine很可能是为了不允许运行潜在危险的程序而设计的，因此我可以看到它们完全禁用线程创建。然而，为什么Google允许您创建一个类，而不允许您调用它的方法呢？白名单的java.util.concurrent是误导性的。

在GAE上是否有其他方法来执行并行/同时/并发任务？