Square matrix guide

import java.util.Random;
import java.util.Scanner;

public class Snippet {
    private final static Scanner s = new Scanner(System.in);
    private final static Random r = new Random();

    public static void main(String[] args) throws Exception {
        print("Enter grid size: ");
        // read grid size
        int n = s.nextInt();

        // spacing
        println();

        // make square grid
        int[][] g = new int[n][n];
        // iterate over indicies in grid, set the value.
        for (int y = 0; y < n; y++) {
            for (int x = 0; x < n; x++) {
                // set value at y:x, then print it
                print(g[y][x] = r.nextInt(2));
            }
            println();
        }

        // spacing
        println();

        // find rows with same values
        for (int y = 0; y < n; y++) {
            // initial value in row-y.
            int row = g[y][0];
            String rowStr = String.valueOf(row);
            String line = rowStr;
            // check and see if value of 'row' changes.
            for (int x = 1; x < n; x++) {
                // if same, add to 'rowStr'
                // if different make 'rowStr' null so we will not add to it
                if (row == g[y][x] && line != null) {
                    // same content
                    line += rowStr;
                } else {
                    // failed
                    line = null;
                }
            }
            // print row string if not null
            if (line != null) {
                println("Row[" + (y + 1) + "]: " + line);
            }
        }


        // spacing
        println();

        // find columns with same values
        // this is mostly the same as the last block of code, but with x/y
        // switched.
        for (int x = 0; x < n; x++) {
            // initial value in col-y.
            int col = g[0][x];
            String colStr = String.valueOf(col);
            String line = colStr;
            // check and see if value of 'col' changes.
            for (int y = 1; y < n; y++) {
                // if same, add to 'colStr'
                // if different make 'colStr' null so we will not add to it
                if (col == g[y][x] && line != null) {
                    // same content
                    line += colStr;
                } else {
                    // failed
                    line = null;
                }
            }
            // print column string if not null
            if (line != null) {
                println("col[" + (x + 1) + "]: " + line);
            }
        }

        // spacing
        println();

        // diagonal-1: top-left --> bottom-right
        int d1 = g[0][0];
        String d1Str = String.valueOf(d1);
        String d1Line = d1Str;
        // diagonal-2: top-right --> bottom-left
        int d2 = g[0][n - 1];
        String d2Str = String.valueOf(d2);
        String d2Line = d2Str;
        for (int d = 1; d < n; d++) {
            // check diagonal 1,
            if (g[d][d] == d1 && d1Line != null) {
                d1Line += d1Str;
            } else {
                d1Line = null;
            }

            // check diagonal 2,
            if (g[d][(n-1)-d] == d2 && d2Line != null) {
                d2Line += d2Str;
            } else {
                d2Line = null;
            }
        }
        // print diagonals
        if (d1Line != null) println("Diagonal-Forwards: " + d1Line);
        if (d2Line != null) println("Diagonal-Backward: " + d2Line);
    }

    private static void println() { System.out.println(); }
    private static void println(Object x) { System.out.println(x); }
    private static void print(Object x) { System.out.print(x); }
}