Static classes in Java - something is hiding

Question

The following is the simplest example of a static inner class in Java. Let's take a look at that.

package staticclass; final class Outer { final public static class Inner { static String s = "Black"; } static Extra Inner = new Extra(); //The inner class name and the object name of the class Extra are same and it is responsible for shadowing/hiding Inner.s } final class Extra { String s = "White"; } final public class Main { public static void main(String[] args) { System.out.println(Outer.Inner.s); } } 

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In the Outer class, there is a static class with the name Internal and a static object with the same name Internal of type Extra. The program displays Whitte on the console, a line in the Extra class through Outer.Inner.s in main (), which is designed to display the line contained in the Internal class in the External class

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Why are there no name clashes between a static inner class and a static Extra object? How does the Extra class take precedence over the Internal class and display the string contained in the Advanced class?

Answer 1

This is what JLS says. which I consider relevant to your case:

6.3.2 Shaded announcements

A simple name can occur in contexts where it can potentially be interpreted as the name of a variable, type, or package. In these situations, the rules of § 6.5 indicate that a variable will be selected in the type preference, and that the type will be selected in the package preference.

So, since your static Extra Inner = new Extra() is a variable, it will be selected over the final public static class Inner , which is a type.

A more detailed paragraph 6.3.1 indicates how shadow copy should normally be performed.

Answer 2

Because the name of the inner class of the inner class is Outer $ Inner. It is a convenience that you can refer to it as an Inner. I assume that the compiler is aware of this and accepts a more explicit rule for the local variable.