Question about the problem of shooting stars using Java for statements

Question

Solving the problem of taking stars in Java. The questions are as follows.

1. Print out a square with a width and length of 10*10 using *.

2. The columns that match the x and y coordinates in the following array list should be outputted 0 instead of *. The complete version and array list are as follows. For example, if an element in an array list is given,

    Character character1  = new Character(5,5);
    Character character2  = new Character(7,8);
    Character character3  = new Character(3,1);
   

The output shall be as follows like this:

* * O * * * * * * * 
* * * * * * * * * * 
* * * * * * * * * * 
* * * * * * * * * * 
* * * * O * * * * * 
* * * * * * * * * * 
* * * * * * * * * * 
* * * * * * O * * * 
* * * * * * * * * * 
* * * * * * * * * * 

This is the code I'm currently writing.

public class Character {
     int xLocation;
     int yLocation;
    public Character(int x, int y){
        this.xLocation = x;
        this.yLocation = y;
    }
    public int getXLocation(){return xLocation;}
    public int getYLocation(){
        return yLocation;
    }
}

import java.util.ArrayList;
public class Main {
    public static void main(String[] args)
    {
        int a = 10;
        
        ArrayList<Character> characters = new ArrayList<>();
        Character character1  = new Character(5,5);
        Character character2  = new Character(7,8);
        Character character3  = new Character(3,1);
        characters.add(character1);
        characters.add(character2);
        characters.add(character3);
        for (int i = 1; i<=a; i++)
        {
            for (int v = 1; v <= a; v++)
            {
                for (int j = 0; j < characters.size(); j++)
                {
                    if (v == characters.get(j).getXLocation() && i == characters.get(j).getYLocation())
                    {
                        System.out.print("O ");
                    }
                    else System.out.print("* ");
                }
                System.out.println();
            }
        }
    }
}

However, the code has the following incorrect output:

* * * 
* * * 
* * O 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
O * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* O * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 
* * * 

Answer 1

The issue is you have the System.out.println() in the wrong place in your nested-loop. Your current solution starts a new line after iterating over all the characters, when really it should start a new line after iterating over all the x-values for a given row (in this case you've named the variable v). This just means moving the System.out.println() out one loop, such as in the following:

import java.util.ArrayList;
public class Main {
    public static void main(String[] args)
    {
        int a = 10;
        
        ArrayList<Character> characters = new ArrayList<>();
        Character character1  = new Character(5,5);
        Character character2  = new Character(7,8);
        Character character3  = new Character(3,1);
        characters.add(character1);
        characters.add(character2);
        characters.add(character3);
        for (int i = 1; i<=a; i++)
        {
            for (int v = 1; v <= a; v++)
            {
                for (int j = 0; j < characters.size(); j++)
                {
                    if (v == characters.get(j).getXLocation() && i == characters.get(j).getYLocation())
                    {
                        System.out.print("O ");
                    }
                    else System.out.print("* ");
                }
            }
            System.out.println(); // Only line changed
        }
    }
}