初始化新对象时的StackOverflow

Question

I have no idea why is this happenning, it seems to be in a constant loop between creating new object and initializing it

public class App {

Character hero = new Character();
charCreation charCreation = new charCreation();

public static void main(String [] args){
    App app = new App();
    app.run();
}
    void run(){
        charCreation.charCreate();

    }




}

So here App creates a new charCreation object which is this

import java.util.Scanner;

class charCreation extends App {

Scanner skan = new Scanner(System.in);

protected  void charCreate(){

......

And here's the error

Exception in thread "main" java.lang.StackOverflowError

at charCreation.(charCreation.java:3)

at App.(App.java:5)

at charCreation.(charCreation.java:3)

at App.(App.java:5)

......

it goes on and on

Answer 1

When you create an instance of CharCreation (fixed CamelCase for you), it will also initialize everything inherited from its superclass App (calling the superclass constructor, initializing all the instance fields, etc). Part of that is creating another instance of CharCreation (as well as an instance of Character ).

Infinite loop.

Maybe you want to remove that instance field from App and make it a local variable in run instead.

Answer 2

The charCreation class extends App so to create it it needs to call the constructor of the superclass ( App ). To construct the App superclass, the fields of App need to be costructed, including a new charCreation() - and so it loops.

You need to decouple creation of a new charCreation object from the creation of the App instance.

Answer 3

You have an App class with a field of type CharCreation .

CharCreation extends App , so when you initialize a CharCreation object, it will initialize the field charCreation . And so, when the charCreation field is initialized, it will initialize a new CharCreation object, and so on.

It's basically a design issue you have to solve, and I think you CharCreation class shouldn't extends the App class, and charCreate should return a Character .

public class App {
    Character hero = new Character();
    CharCreation charCreation = new charCreation();

    void run(){
        hero = charCreation.charCreate();

    }
}

public class CharCreation {
   public Character charCreate() {
       /* creates and returns the hero */
   }
}

Side note:

• Always name your classes with a first upper letter to match the java convention, CharCreation and not charCreation .
• Don't use Character to name a class, it's a class which already exist in the JDK (the object counterpart of char ).

Answer 4

Cyclic object creation which caused stackoverflow.

1. App object create charCreation instance object

2. charCreation object will also create App Object as it is super class.[super class object instantiate before child]

3. Cycle found, go on... till the stackoverflow.