Thread java

import java.io.IOException;
import java.io.InputStream;


class Well {
 private String name;
 private int water;
 private Object waterLock = new Object();
 
 
 public Well(String name, int initial) {
  this.name = name;
  this.water = initial;
 }
 
 public void draw(int waterL) {
  water = water - waterL;
 }
 
 public void pour(int waterL) {
  synchronized(waterLock) {
   water = water + waterL;
  }
 }

 public int getWater() {
  return water;
 }
}

class Person {
 private String name;
 private int water = 10;
 
 private Well well;
 
 public Person(String name, Well well) {
  this.name = name;
  this.well = well;
 }
 
 public void drawFromWell(int waterL) {
  well.draw(waterL);
  water = water + waterL;
 }
 
 public void pourIntoWell(int waterL) {
  well.pour(waterL);
  water = water - waterL;
 }
}

class ActionThread  extends Thread {
 Person person;
 
 public ActionThread(Person person) {
  this.person = person;
 }
 
    public void run() {
     for (int j = 0 ; j < 100; j++) {
      for (int i = 0; i < 1000000; i++) {
       person.pourIntoWell(1);
      }
      
     }
    }
}

class ActionThread2  extends Thread {
 Person person;
 
 public ActionThread2(Person person) {
  this.person = person;
 }
 
    public void run() {
     for (int j = 0 ; j < 100; j++) {
      for (int i = 0; i < 1000000; i++) {
       person.pourIntoWell(1);
      }
     }
    }
}

public class Main {
 
 public static void main(String[] args) {
  
  Well well = new Well("There is a well", 100);
  Well well2 = new Well("There is another well", 100);
  
  Person p1 = new Person("Person A", well);
  Person p2 = new Person("Person B", well2);
  
  ActionThread a = new ActionThread(p1);
  ActionThread2 b = new ActionThread2(p2);
  
  long start = System.currentTimeMillis();
  
  b.start();
  a.start();
  
  try {
   a.join();
   b.join();
  } catch (InterruptedException e) {
   e.printStackTrace();
  }
  
  long end = System.currentTimeMillis();
  
  System.out.println("elasped : " + (end- start));
  System.out.println(well.getWater());
  
 }

}