Hello I was wondering If someone can help me understand this concept in Java. Can you use the provided example to make a quick example for me to follow with?

EXAMPLE:

Public class Zoo$\{$

$//$Zoo class members $($instance vars, constructors, setter$/$getters$,$ etc.$)$

$\}$

Public class Animal$\{$

Zoo animal $=$ new Zoo$()$; $//$instance var of Zoo

$//$ Animal class members $($instance vars, constructors, setters$/$getters$,$ etc.$)$

$\}$

All I really know is that Animal class $($second class$)$ is supposed to have field type from class Zoo$($First defined class$)$ and neither class should have main in them.

TIA!