java块，直到Executor服务完成

Question

Possible Duplicates:
ExecutorService, how to wait for all tasks to finish
Java ExecutorService: awaitTermination of all recursively created tasks

有没有办法阻止当前线程，直到ExecutorService完成所有任务

executor.execute(task1);
executor.execute(task2);
executor.execute(task3);
executor.execute(task4);
executor.execute(task5);
// ...now I want to block until all tasks have finished executing...
System.out.println("done!")