java - java中的.class文件

Question

任何人都可以指导我解决这个问题(记住这个问题是在 Java Reflection 上下文中)

There are is a java class named "A" having an inner class named "B".When i compile this java file then it create 2 versions of .class file one named as "A.class" & "A$B.class" and If "A" class have 2 inner classes i.e B,C then there will be 3 version created "A.class" & "A$B.class" & "A$C.class"
Why this is happen.

And if i want to read the .class file then what .class file i read b/c when i gave A.class then it will ask for A$B.class and give Caused by: java.lang.ClassNotFoundException: A$B.class

如果我们给出 A$B.class 那么它会给出异常

java.lang.NoClassDefFoundError: 
java.lang.ClassNotFoundException


class A {
 String _name="Tom";
    class B{
        int _phoneNo=8384040;  
    }
}

Answer 1

There are is a java class named "A" having an inner class named "B"

所以你有两个类，并且应该有两个类文件。

If "A" class have 2 inner classes i.e B,C

您有三个类和三个类文件。

And if i want to read the .class file then what .class file i read b/c when i gave A.class then it will ask for A$B.class

当你读取A.class文件时，你只是在读取一个文件。它不会要求您提供任何其他信息。

and give Caused by: java.lang.ClassNotFoundException: A$B.class

只有当此类不在您的类路径中时才会发生这种情况，这是完全不同且不相关的事情。

<小时/>

这是加载类的方式，但创建这些类的实例。无需读取底层类，甚至无需知道它们在磁盘上的排列方式。

 A a = new A(); // creates an instance of A
 A.B b = a.new A.B(); // creates an instance of A.B which is "inside" 'A a'.