关于hashmap在多线程环境下的一个小实验

import java.util.HashMap;
public class TestMap {
 private HashMap map = new HashMap(2, 0.5f);
 public TestMap() {
  Thread t1 = new Thread() {
   public void run() {
    for (int i = 0; i < 50000; i++) {
     map.put(new Integer(i), i);
    }
    System.out.println("t1 over");
   }
  };
  Thread t2 = new Thread() {
   public void run() {
    for (int i = 0; i < 50000; i++) {
     map.put(new Integer(i), i);
    }
    System.out.println("t2 over");
   }
  };
  Thread t3 = new Thread() {
   public void run() {
    for (int i = 50000; i < 100000; i++) {
     map.put(new Integer(i), i);
    }
    System.out.println("t3 over");
   }
  };
  Thread t4 = new Thread() {
   public void run() {
    for (int i = 100000; i < 150000; i++) {
     map.put(new Integer(i), i);
    }
    System.out.println("t4 over");
   }
  };
  Thread t5 = new Thread() {
   public void run() {
    for (int i = 150000; i < 200000; i++) {
     map.put(new Integer(i), i);
    }
    System.out.println("t5 over");
   }
  };
  Thread t6 = new Thread() {
   public void run() {
    for (int i = 0; i < 50000; i++) {
     map.get(new Integer(i));
    }
    System.out.println("t6 over");
   }
  };
  Thread t7 = new Thread() {
   public void run() {
    for (int i = 50000; i < 100000; i++) {
     map.get(new Integer(i));
    }
    System.out.println("t7 over");
   }
  };
  Thread t8 = new Thread() {
   public void run() {
    for (int i = 100000; i < 150000; i++) {
     map.get(new Integer(i));
    }
    System.out.println("t8 over");
   }
  };
  t1.start();
  t2.start();
  t3.start();
  t4.start();
  t5.start();
  t6.start();
  t7.start();
  t8.start();
 }
 public static void main(String[] args) {
  new TestMap();
 }
}