Hani Goc Hani Goc - 6 months ago 41
Java Question

Object instantiation: Inner class and outer class with the same name (Java)

Code description and ouput

In the following code. We have a class TestInners, one inner class A, one method local inner class A and one outer class A.

  1. When we instantiate an object as in
    new A().m();
    the ouput is

  2. In order for the program to output inner we must instantiate the object after the method local inner class A in the gomethod.

  3. If we comment the inner class the program will output outer.


In the code as it is. Why did it output middle? Is there a preference for the inner classes first? then the outer classes? I got confused.

Source code

class A { void m() { System.out.println("outer"); } }

public class TestInners {
public static void main(String[] args) {
new TestInners().go();
void go() {
new A().m();
class A { void m() { System.out.println("inner"); } }

class A { void m() { System.out.println("middle"); } }


Yes, if you shadow symbols with more local definitions, the more local one is chosen. This most frequently happens with method parameters vs instance fields, leading to the famous this.name = name idiom.

In your case, you can get to the outer class by using a fully qualified class name.

But don't name classes like that. Too much confusion for no reason.