Thread: Beginner question on where to put an array

A typical design would be to create a new class that defines your data model - I would not extend the Arrays class (in fact, don't even see how this would be beneficial as all the Arrays class contains are static methods), rather write your own to encapsulate your data within this class. In this way, a change to the model is reflected in all references to said model

What kind of information would this data model have in it?

Whatever information you wish. Java is object oriented, so create classes which make sense. For instance you wish to model a Hospital...so create a class Hospital. This class could contain a List/array of patients which can be accessed using methods you define (like addPatient, getPatient, etc...).

public class Hospital{
    //define your patients inside this class
 
    ///getter, setter, and add methods can be defined here
}

This makes sense from both an object oriented standpoint and from an encapsulation standpoint (encapsulation meaning you 'hide' how Patients from stored from other classes, meaning you could use an array, a List, a Map, and change these as you see fit without breaking your whole project).

Not necessarily an inner class by definition, and not necessarily public or static either (static means that if you make more hospitals, the patients will be shared - not what you want - and public defeats the purpose of trying to encapsulate things). I'd suggest that it should still be a separate class, Hospital just contains instances/Objects of that class. Don't think too hard about it...start laying out some code and think about what things represent - should they be a class of their own

See the following link for code conventions in java: Code Conventions for the Java Programming Language which may address your questions of where to place things.