我有一个mareduce作业作为jar文件，比如'mapred.jar'。实际上jobtracker是在远程linux机器上运行的。我在本地机器上运行jar文件，jar文件中的作业被提交到远程jobtracker，工作正常，如下所示：

java -jar F:/hadoop/mapred.jar

13/12/19 12:40:27 WARN mapred.JobClient: Use GenericOptionsParser for parsing th
     e arguments. Applications should implement Tool for the same.
     13/12/19 12:40:27 INFO input.FileInputFormat: Total input paths to process : 49
     13/12/19 12:40:27 WARN util.NativeCodeLoader: Unable to load native-hadoop libra
     ry for your platform... using builtin-java classes where applicable
     13/12/19 12:40:27 WARN snappy.LoadSnappy: Snappy native library not loaded
     13/12/19 12:40:28 INFO mapred.JobClient: Running job: job_201312160716_0063
     13/12/19 12:40:29 INFO mapred.JobClient:  map 0% reduce 0%
     13/12/19 12:40:50 INFO mapred.JobClient:  map 48% reduce 0%
     13/12/19 12:40:53 INFO mapred.JobClient:  map 35% reduce 0%
     13/12/19 12:40:56 INFO mapred.JobClient:  map 29% reduce 0%
     13/12/19 12:41:02 INFO mapred.JobClient:  map 99% reduce 0%
     13/12/19 12:41:08 INFO mapred.JobClient:  map 100% reduce 0%
     13/12/19 12:41:23 INFO mapred.JobClient:  map 100% reduce 100%
     13/12/19 12:41:28 INFO mapred.JobClient: Job complete: job_201312160716_0063
      ...

但当我通过java的processbuilder执行相同的操作时，如下所示：

ProcessBuilder pb = new ProcessBuilder("java", "-jar", "F:/hadoop/mapred.jar");
    pb.directory(new File("D:/test"));
    final Process process = pb.start();
    InputStream is = process.getInputStream();
    InputStreamReader isr = new InputStreamReader(is);
    BufferedReader br = new BufferedReader(isr);
    String line;
    while ((line = br.readLine()) != null) {
      System.out.println(line);
    }

    System.out.println("Waited for: "+ process.waitFor());
    System.out.println("Program terminated! ");

它也起作用了，我可以通过， http://192.168.1.112:50030/jobtracker.jsp .
问题
我的问题是，即使mapreduce作业完成了，java程序也不会无限期地运行！。我也没有得到任何输出消息，我通过命令行得到。我怎么知道工作得到完成？