class Member {
  private static int counter = 0;
  private int id = ++counter;
  public Member() {
    System.out.println(
      "Member constructor " + id);
  }
}

class Rodent3 {
  Member m = new Member();
  public Rodent3() {
    System.out.println("Rodent constructor");
  }
  public void hop() {
    System.out.println("Rodent hopping");
  }
  public void scurry() {
    System.out.println("Rodent scurrying");
  }
  public void reproduce() {
    System.out.println("Making more Rodents");
  }
  public String toString() {
    return "Rodent";
  }
}

class Mouse3 extends Rodent3 {
  Member m = new Member();
  public Mouse3() {
    System.out.println("Mouse constructor");
  }
  public void hop() {
    System.out.println("Mouse hopping");
  }
  public void scurry() {
    System.out.println("Mouse scurrying");
  }
  public void reproduce() {
    System.out.println("Making more Mice");
  }
  public String toString() {
    return "Mouse";
  }
}

class Gerbil3 extends Rodent3 {
  Member m = new Member();
  public Gerbil3() {
    System.out.println("Gerbil constructor");
  }
  public void hop() {
    System.out.println("Gerbil hopping");
  }
  public void scurry() {
    System.out.println("Gerbil scurrying");
  }
  public void reproduce() {
    System.out.println("Making more Gerbils");
  }
  public String toString() {
    return "Gerbil";
  }
}

class Hamster3 extends Rodent3 {
  Member m = new Member();
  public Hamster3() {
    System.out.println("Hamster constructor");
  }
  public void hop() {
    System.out.println("Hamster hopping");
  }
  public void scurry() {
    System.out.println("Hamster scurrying");
  }
  public void reproduce() {
    System.out.println("Making more Hamsters");
  }
  public String toString() {
    return "Hamster";
  }
}


public class E10_RodentInitialization {
  public static void main(String args[]) {
    new Hamster3();
  }
}
输出应该是:
Member constructor 1
Member constructor 2
Rodent constructor
Member constructor 7
Member constructor 8
Hamster constructor

我用javac命令运行不能成功，但是用JCreator编译器能运行结果是
Member constructor 1
Rodent constructor
Member constructor 2
Hamster constructor
不知道为什么会这样！！！！

这是thinking in java书中的一道练习题的答案，他应该想告诉我们怎样初始化吧