I don't understand why the program uses System.out.println(new GenerateThread()) in main but also in run. What is the difference? 
package com.codegym.task.task16.task1623;

/*
Creating threads recursively

*/

public class Solution {
    static int count = 15;
    static volatile int createdThreadCount;

    public static void main(String[] args) throws InterruptedException {
          System.out.println(new GenerateThread());
    }
    public static class GenerateThread extends Thread {
        public GenerateThread() {
            super(String.valueOf(++createdThreadCount));
            start();
        }
            @Override
            public String toString() {
                return getName() + " created";
            }

            public void run() {
                if (createdThreadCount < count) System.out.println(new GenerateThread());
            }
    }
}