看到这个题目,我也不明白为什么Cookie 类的静态代码没有执行.如果类加载了这个static代码就应该执行啊。如果没加载,怎么能使用Cookie.class属性呢
class Candy {
static
{
System.out.println("Loading Candy");
}
} class Gum
{
static
{
System.out.println("Loading Gum");
}
} class Cookie
{
static
{
System.out.println("Loading Cookie");
}
} public class SweetShop {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("inside main");
new Candy();
System.out.println("After creating Candy");
try
{
Class.forName("Gum");
}
catch(ClassNotFoundException e)
{
e.printStackTrace();
}
System.out.println("After Class.forName(\"Gum\")");
Class c = Cookie.class;
System.out.println("Cookie toString(): " + c);
System.out.println("After creating Cookie");
} }
class Candy {
static
{
System.out.println("Loading Candy");
}
} class Gum
{
static
{
System.out.println("Loading Gum");
}
} class Cookie
{
static
{
System.out.println("Loading Cookie");
}
} public class SweetShop {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("inside main");
new Candy();
System.out.println("After creating Candy");
try
{
Class.forName("Gum");
}
catch(ClassNotFoundException e)
{
e.printStackTrace();
}
System.out.println("After Class.forName(\"Gum\")");
Class c = Cookie.class;
System.out.println("Cookie toString(): " + c);
System.out.println("After creating Cookie");
} }
{
Class.forName("Gum");
}
catch(ClassNotFoundException e)
{
e.printStackTrace();
}
这段代码有问题,出现异常
实际上,在编译期,这个已经决定下来了再比如 static final int 的常量,你访问,并不会造成对指定类的载入,这个东西再编译期已经内联了
http://community.csdn.net/Expert/topic/5478/5478850.xml?temp=.9950983
? 测试了下,发现 类.class 这个东西,不能代表对类的访问
实际上,在编译期,这个已经决定下来了再比如 static final int 的常量,你访问,并不会造成对指定类的载入,这个东西再编译期已经内联了
------------------------------------------------
有道理!绝对支持!
这是你的那个SweetShop类反编译的结果:看了就知道了.
import java.io.PrintStream;public class SweetShop
{ public SweetShop()
{
} public static void main(String args[])
{
System.out.println("inside main");
new Candy();
System.out.println("After creating Candy");
try
{
Class.forName("Gum");
}
catch(ClassNotFoundException classnotfoundexception)
{
classnotfoundexception.printStackTrace();
}
System.out.println("After Class.forName(\"Gum\")");
Object obj = Cookie;//<-------------------------------------------------------这儿!
System.out.println((new StringBuilder()).append("Cookie toString(): ").append(obj).toString());
System.out.println("After creating Cookie");
}
}
java编译器在编译过程中已经将这些类的信息复制了一份
访问的时候不用加载就可以直接获取信息
inside main
Loading Candy
After creating Candy
Loading Gum
After Class.forName("Gum")
Loading Cookie
Cookie toString(): class Cookie
After creating Cookie