如何在没有引用的情况下创建静态类Object？

Question

I was trying to solve problems of LinkedList through Java, But I found out the concept of static inner class and I am stuck here!

My code is working, But could not understand how the static class object is being Created

public class findNthNodeInLL {
    static class Node {
       int data;
       Node next;

       Node(int data) {
          this.data = data;
          next = null;
       }
    }

int findNthNode(Node head, int count) {
    int pos = 0;
    Node ptr = head;

    while(ptr != null && pos != count) {
        pos++;
        ptr = ptr.next;
    }

    return ptr.data;
}

public static void main(String[] args) {
    findNthNodeInLL ll = new findNthNodeInLL();
    Node head = new Node(1);
    head.next = new Node(2);
    head.next.next = new Node(3);
    head.next.next.next = new Node(4);
    head.next.next.next.next = new Node(5);

    System.out.println(ll.findNthNode(head,3));
}
}

The Inner class Object ie head is being created without any reference of the outer class. Even the constructor is being called and the memory is being created without any outer class reference.

What is the actual scenario over here? What is happening? Why are we not using any outer class reference for the inner class constructor or object?

Maybe I am missing something. Please help me understand the scenario over here.

Answer 1

You are using the static class inside the outer class itself so You don't to put the enclosing class name. A static nested class is behaviorally like any over static fields.

But If you want to instantiate the static nested class outside the outer class, you have to put the enclosing class name or use reference to the outer class on its definition.

For example :

public class Main {
static class NodeInside {
    int data;
    NodeX.Node next;

    NodeInside(int data) {
        this.data = data;
        next = null;
    }
}
public static void main(String[] args) {
    NodeX ll = new NodeX();
    NodeX.Node head = new NodeX.Node(1); // need to put the enclosing class name
    NodeInside nodeInside = new NodeInside(1); // no need to put the enclosing class 
  }
}

class NodeX{
static class Node {
    int data;
    Node next;

    Node(int data) {
        this.data = data;
        next = null;
    }
}
}