isSymmetric

public static boolean isSymmetric(int[][] m) {
        if (m == null) return false;
        for (int[] row : m) if (row == null) return false;

        int tempRowLength = m[0].length;
        for (int[] row : m) if (row.length != tempRowLength) return false;

        return Arrays.deepEquals(m, getTransposedMatrix(m));
    }