import  java.util.HashMap;
 import  java.util.Iterator;
 import  java.util.concurrent.*;

 public   class  MyThread  implements  Runnable {

     private  ExecutorService executorService = Executors.newCachedThreadPool();

     private  HashMap<Future,  Long > tasks =  new  HashMap<Future,  Long >();

     private  Thread runner;

     public  MyThread(String[] hosts) {
         for  ( final  String host : hosts) {
            FutureTask<String> future =
                     new  FutureTask<String>( new  Callable<String>() {
                         public  String call() {
                            /**
                             * Ваш код
                             * sess.execCommand("sudo -u differ rsh "+switchList.elementAt(i).toString().trim()+" sh mac-address-table | grep -v Gi | grep -v CPU");
                             * ...
                             */
                             return  host;
                        }
                    });
            executorService.execute(future);
            tasks.put(future, System.currentTimeMillis());
        }
    }

     public   void  start() {
        runner =  new  Thread( this );
        runner.start();
    }

     public   static   void  main(String [] args) {
        String [] s = {"host1", "host2", "host3", "host4", "host5", "host6", "host7"};
        MyThread thread =  new  MyThread(s);
        thread.start();
    }

     public   void  run() {
         while (!tasks.isEmpty()) {
             for  (Iterator<Future> iter = tasks.keySet().iterator(); iter.hasNext();) {
                Future future = iter.next();
                 boolean  isTimeout = System.currentTimeMillis() - tasks.get(future) >  2 * 60 * 1000 ;
                 if  (future.isDone()) {
                    iter.remove();
                }  else   if  (isTimeout) {
                    future.cancel(true);
                    iter.remove();
                }
            }
             try  {
                Thread.sleep( 100 );
            }  catch  (InterruptedException e) {
                e.printStackTrace();
            }
        }
        executorService.shutdown();        
    }

}