Распределенное программирование на языке Java с использованием обменников

import java.util.concurrent.*;
 
class DataClass {
  int value;
  String message;
 
  DataClass( int v, String s) {
    value = v; message = s;
    }
  int getValue() { return( value); }
  String getMassage() { return( message); }
  }
 
class Loop implements Runnable {
  int counter;
  String name;
  Exchanger<DataClass> exchanger;
 
  Loop( int startValue, String id, Exchanger<DataClass> ex) {
    counter = startValue;
    name = id; exchanger = ex;
    System.out.println( name + ": created");
    }
 
  public void run() {
    System.out.println( name + ": started");
    DataClass data = new DataClass( counter, name);
    for (int i = 0; i < 3; ++i) {
      try {
        DataClass newData = exchanger.exchange( data);
        counter += newData.getValue();
        System.out.println( name + ": from " + 
          newData.getMassage() + ": data: " + 
          newData.getValue() + ": state = " + counter);
        }
      catch (InterruptedException e) {
        System.err.println( e.toString());
        }
      }
    System.out.println( name + ": ended");
    }
  }
 
public class ExchangerDemo {
  public static void main( String args[]) {
    System.out.println( "Main process started");
    Exchanger<DataClass> exchanger = new Exchanger<DataClass>();
    Loop loop1 = new Loop( 1, "First", exchanger);
    Loop loop2 = new Loop( 2, "Second", exchanger);
    new Thread( loop1).start();
    new Thread( loop2).start();
    System.out.println( "Main process ended");
    }
  }