自己無任何程式語言基礎，想自學爬文說到java深入淺出著本書適合入門用，最近看到第二章就g了，因為書上寫只有2個類別但是我怎麼看著段程式碼都是4個類別。
跪求神解
文章是寫有2個class物件程式碼如下:
(自己是用Eclipse編輯的)
著是Dog
public class Dog {
int size;
String breed;
String name;
{
{
Dog d = new Dog();
d.size = 40;
d.bark();
}
}

void bark(){
System.out.println("Ruff! Ruff!");
}
}

著是Movie
public class Movie {
String title;
String genre;
int rating;

void platIt() {
System.out.println("Playing the movie");

}
}

著是DogTestDrive
public class DogTestDrive {
public static void main (String[] args) {
Dog d = new Dog();
d.size = 40;
d.bark();
}
}

著是MovieTestDrive
public class MovieTestDrive {
public static void main (String[] args) {
Movie one = new Movie ();
one.title = "Gone with the Stock";
one.genre = "Tragic";
one.rating = -2;
Movie two = new Movie();
two.title = "Lost in Cubicle Space";
two.genre = "Comedy";
two.rating = 5;
two.platIt();
Movie three = new Movie();
three.title = "Byte Club";
three.genre = "Tragic but ultimately uplifting";
three.rating = 127;
}
}