Tried printing out the rows in a 2d matrix using this code:

class Main {  
  public static void main(String args[]) { 
    int[][]matrix = { {1,2,3},
                   {4,5,6},
                   {7,8,9},
                   {1,2,1} };
                   
                 
    for(int[] row: matrix){
        System.out.println(row);
    }

  } 
  
}

It doesn't work. I get this on the compiler:

[I@76ed5528
[I@2c7b84de
[I@3fee733d
[I@5acf9800

What's going on?

Hello everyone,

for a uni assignment I have to write a method that prints a grid view of a list of titles with three titles in a row. To achieve that, my idea is to first trim pr pad the titles so they have the same length, then create a two dimensional array with three titles in each subarray. Lastly, I want to loop through the array (of arrays) and print each subarray in one row. The padding and trimming works just fine, but there seems to be a problem with the creation of the 2D-array. When I try to print it, nothing happens. The code compiles just fine though. It looks like this:

    public void printGridView()
    {
        // First, get all currently stored titles and trim them to size

        String[] fittedTitles = new String[movies.size()];
        String fittedTitle = "";
        int index = 0;
        
        for (Movie movie : movies) {
            int len = movie.getTitleLength(movie.getTitle());

            if (len > 21){
                fittedTitle = movie.trimTitle(movie.getTitle());
            } else if (len < 21) {
                fittedTitle = movie.padTitle(movie.getTitle());
            }

            fittedTitles[index] = fittedTitle + " (" + movie.getYearOfRelease() + ")"; // add the year to the array for easier printing
            index++;
        }

        
        // Next, create an array for each row of threes to be printed

        int rest = fittedTitles.length % 3; // determine whether there is an array with less than 3 columns
        int chunks = fittedTitles.length / 3 + (rest > 0 ? 1 : 0); //adds an extra array if there is a rest
        String[][] arrays = new String[chunks][];
        

        for (int i = 0; i < (rest > 0 ? chunks - 1 : chunks); i++) {
            arrays[i] = Arrays.copyOfRange(fittedTitles, i * 3, i * 6); // Exception with copyOfRange: array building doesn't work correctly. 
        }

        if (rest > 0){
            arrays[chunks-1] = Arrays.copyOfRange(fittedTitles, (chunks-1) * 3, (chunks-1) *  (3 + rest)); // makes an extra array with less than three titles
        }
        
        // quick test if array was built correctly
        for (int i = 0; i < arrays.length; ++i) {
            for(int j = 0; j < arrays[i].length; ++j) {
                System.out.println(arrays[i][j]);
            }
        }
        
        // Finally, print each row of threes accordingly

        int i = 0;

        if (rest == 0) { // in case of even rows of threes
            for (i = 0; i < arrays.length; i++) {
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("|| " + arrays[i][0] + " || " + arrays[i][1] + " || " + arrays[i][2] + " ||");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
            }
        } else if (rest == 2) { // in case of uneven rows with 2 left
            String[] array = arrays[i]; 
            while (i < (arrays.length-1)) {
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("|| " + array[0] + " || " + array[1] + " || " + array[2] + " ||");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
                i++;
            }
            System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
            System.out.println("||                            ||                            ||");
            System.out.println("|| " + array[0] + " || " + array[1] + " ||");
            System.out.println("||                            ||                            ||");
            System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
        } else {
            String[] array = arrays[i]; 
            while (i < (arrays.length-1)) { // in case of uneven rows with one left
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("|| " + array[0] + " || " + array[1] + " || " + array[2] + " || ");
                System.out.println("||                            ||                            ||                            ||");
                System.out.println("||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
                i++;
            }
            System.out.println("||||||||||||||||||||||||||||||||");
            System.out.println("||                            ||");
            System.out.println("|| " + array[0] + " ||");
            System.out.println("||                            ||");
            System.out.println("||||||||||||||||||||||||||||||||");
        }

    }

When I try to print the 2D-array into the grid view, I get the exception

"java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0".

I have tried to recreate a case of 3 titles by hand and found no mistakes, I feel like it should work or at least give me the same errors for both ways of printing and I'm at my wits end.

Can somebody help please?