So I have a polymorphism & inhertiance problem, according to the solution given in class y$.$Do$3$ and z$.$Do$3$ should both output an error but when I do it myself only y$.$Do$3$ outputs an error and z$.$Do$3$ outputs Do$3$:lake $->$Do$2$:pond, can someone explain what is correct?

Consider the following class hierarchy:

public class Pond $\{$

Public void Do$2()\{$

System.out.println$($Do$2$: Pond$)$;$\}$

$\}$

public class Lake extends Pond $\{$

Public void Do$3()\{$

System.out.println$($Do$3$: Lake$)$;

Do$2()$; $\}$

$\}$

public class Bay extends Lake $\{$

Public void Do$1()\{$

System.out.println$($Do$1$: Bay$)$;

super.Do$2()$;

$\}$

Public void Do$2()\{$

System.out.println$($Do$2$: Bay$)$;

$\}$

$\}$

public class Ocean extends Bay $\{$

Public void Do$2()\{$

System.out.println$($Do$2$: Ocean$)$;

$\}\}$

Show the output after executing the following code:

public class MainClass$\{$

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

Lake X $=$ new Ocean$()$;

Pond Y $=$ new Pond$()$;

Pond Z $=$ new Lake$()$;

Lake W $=$ new Bay$()$;

Bay M $=$ new Ocean$()$;

X$.$Do$2()$;

Y$.$ Do$2()$;

Z$.$ Do$2()$;

W$.$ Do$2()$;

M$.$ Do$2()$;

X$.$ Do$3()$;

Y$.$ Do$3()$;

Z$.$ Do$3()$;

W$.$ Do$3()$;

M$.$ Do$3()$;

$\}//$ end main

$\}//$ end of MainClass