我试图从 Thinking in Java 中理解这个例子:
package c07;
import com.bruceeckel.simpletest.*;
class Meal {
Meal() { System.out.println("Meal()"); }
}
class Bread {
Bread() { System.out.println("Bread()"); }
}
class Cheese {
Cheese() { System.out.println("Cheese()"); }
}
class Lettuce {
Lettuce() { System.out.println("Lettuce()"); }
}
class Lunch extends Meal {
Lunch() { System.out.println("Lunch()"); }
}
class PortableLunch extends Lunch {
PortableLunch() { System.out.println("PortableLunch()");}
}
public class Sandwich extends PortableLunch {
private static Test monitor = new Test();
private Bread b = new Bread();
private Cheese c = new Cheese();
private Lettuce l = new Lettuce();
public Sandwich() {
System.out.println("Sandwich()");
}
public static void main(String[] args) {
new Sandwich();
monitor.expect(new String[] {
"Meal()",
"Lunch()",
"PortableLunch()",
"Bread()",
"Cheese()",
"Lettuce()",
"Sandwich()"
});
}
}
正如我从 Java 语言规范中了解到的那样,执行顺序从加载包含 main 方法的类开始。然后必须初始化这个类的所有静态变量和成员变量(在此之前必须初始化超类的所有成员变量,尽管在这种情况下没有这些成员变量)。
所以我认为b
,c
会在开始执行l
之前被初始化。main
不过,从输出来看,情况似乎并非如此。我错过了什么吗?