Can the rows in a two$-$dimensional array have different lengths?

$2)$ What is the output of the following code?

int$[][]$ array $=$ new int$[5][6]$;

int$[]$ x $=\{1,2\}$;

array$[0]=$ x;

System.out.println$("$array$[0][1]$ is $"+$ array$[0][1])$;

$3)$ Show the output of the following code:

int$[][]$ array $=\{\{1,2\},\{3,4\},\{5,6\}\}$;

for $($int i $=$ array.length $-1$; i $>=0$; i$--)\{$

for $($int j $=$ array$[$i$].$length $-1$; j $>=0$; j$--)$

System.out.print$($array$[$i$][$j$]+"")$;

System.out.println$()$;

$\}$

$4)$ Show the output of the following code:

public class Test $\{$

public static void main$($String$[]$ args$)\{$

int$[][]$ array $=\{\{1,2,3,4\},\{5,6,7,8\}\}$;

System.out.println$($m$1($array$)[0])$;

System.out.println$($m$1($array$)[1])$;

$\}$

public static int$[]$ m$1($int$[][]$ m$)\{$

int$[]$ result $=$ new int$[2]$;

result$[0]=$ m$.$length;

result$[1]=$ m$[0].$length;

return result;

$\}$

$\}$