CODEWITHSUNDEEP
javaout-of-memorystack-overflowpanel
IsmaElzem
IsmaElzem

Reputation: 109

StackOverflowError - Jaja

I'm trying to do a simple code in Java : I have a class called "Bloc", which create blocks (square), which inside it I create a random width (largeur), and a random height (hauteur) between 2 ints, and I create a random number of blocks (nombreBloc). I also create an ArrayList to put every block in it, to see how much I have left.

So, I did a function called "insererBlocList" (insert the block into the ArrayList), which create "nombreBloc" (numberBloc) of blocks and put it into the ArrayList.

I've got a graphic interface, in which I have 1 panel for the windows, which inside it I have 2 other panels: One of them is to put every block I created into it.

Here is my problem, I've got a "StackOverflowError" inside my function "insererBlocList", which means there is an infinite loop, but after writing the path of code, I don't see where I did the mistake... Here is the code :

Bloc class:

public class Bloc extends JPanel{
    private int hauteur, largeur, nombreBloc;
    private boolean premierPassage = true;
    private ArrayList<Bloc> listeBlocRestant;
    private Random rand = new Random();

public Bloc() {
    this.hauteur = 10 + rand.nextInt(50 - 10);
    this.largeur = 10 + rand.nextInt(50 - 10);      
    listeBlocRestant = new ArrayList<Bloc>();
    if(premierPassage == true) {
        this.nombreBloc = 5 + rand.nextInt(30 - 5);
        insererBlocList();
    }
}

public ArrayList<Bloc> insererBlocList(){
    premierPassage = false;
    for(int i=0; i<nombreBloc; i++) {       
        Bloc bloc = new Bloc();
        listeBlocRestant.add(bloc);
    }
    return listeBlocRestant;
}

The GUI part of the panel block:

    private JPanel initPanelBloc() {
     panelBloc = new Bloc();
   }

Upvotes: 0

Views: 82

Answers (2)

dhkim0800
dhkim0800

Reputation: 111

You might thought premierPassage = false; will prevent method calling again. But insererBlocList() makes new instance of Bloc and this boolean value will be true again. Change code like this:

public class Bloc extends JPanel{
    private int hauteur, largeur, nombreBloc;
    private ArrayList<Bloc> listeBlocRestant;
    private Random rand = new Random();

public Bloc(boolean premierPassage) {
    this.hauteur = 10 + rand.nextInt(50 - 10);
    this.largeur = 10 + rand.nextInt(50 - 10);      
    listeBlocRestant = new ArrayList<Bloc>();
    if(premierPassage == true) {
        this.nombreBloc = 5 + rand.nextInt(30 - 5);
        insererBlocList();
    }
}

public ArrayList<Bloc> insererBlocList(){
    premierPassage = false;
    for(int i=0; i<nombreBloc; i++) {       
        Bloc bloc = new Bloc(false);
        listeBlocRestant.add(bloc);
    }
    return listeBlocRestant;
}

And change GUI part like this:

private JPanel initPanelBloc() {
     panelBloc = new Bloc(true);
}

Upvotes: 2

Eran
Eran

Reputation: 393856

Your Bloc constructor calls insererBlocList(), and insererBlocList() creates additional Bloc instances (for each of them the constructor calls insererBlocList()), which leads to an infinite chain of method calls, leading to StackOverflowError.

insererBlocList() probably shouldn't be called by the Bloc constructor.

Upvotes: 5

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