public class ModifyCounter extends Thread {
  Counter counter;
  boolean increment;
  static final int SIZE = 10000;

  ModifyCounter(Counter c, boolean incr, String name) { 
    super(name); 
    counter = c; 
    increment = incr; 
  }

  public void run() {
    for(int i=0; i<SIZE; i++)
      if(increment)
        counter.increment();
      else
        counter.decrement();
        
    System.out.println(getName() + ". Counter is: "+counter.value());
  }
  
  public static void main(String []args) {
    Counter c = new Counter();
    new ModifyCounter(c, true, "IncreaseThread").start();
    new ModifyCounter(c, false, "DecreaseThread").start();
  }
}