How to visualize a Stream object (and some other data types)?

I want to make a small programming tutorial which will have a number of images visualizing various data types, but I am not sure how to draw these images of the data types.

Assume that I have a FileOutputStream object that writes to the file 1.txt.

How can I think of this FileOutputStream object, do I think about it as a container of the stream of data (i.e. a pipe), for example:

Or do I think about it as the stream of data only, for example:

I think the term "stream of water" in real life only means the flowing water (without having a container that contains the flowing water).

My question also apply to other data types, for example do I think of a Stack of integers as the container of the stack of integers, for example:

Or do I think about it as the stack of integers only, for example:

I think the term "stack of books" in real life only means the stacked books (without having a container that contains the stacked books).

Same thing for the int data type, do I think of an int as the container of the integer, for example:

Or do I think about it as the integer only, for example:

Take a look at the Java tutorials for IO streams: https://docs.oracle.com/javase/tutorial/essential/io/streams.html and how it illustrates it:

I think the question is somewhat subjective. The "container" helps make the representation more clearer by having clear outlines for the different components in the image (as in the above example). It may also give context to the reader: e.g. for the stack it makes sense to represent it as a container as it is a collection that holds elements. But for an int, what does it represent? Memory allocation?

Keep in mind that at the end, it's just an abstract representation of the concept.

It's always containers.

Let me start from the bottom, because I think it will be easier.

Without getting too far inside memory management specifics, you have to think of everyone as the CONTAINER plus THE DATA. Specially in typed types.

Something, without the container, is just bits.

Example: An integer 4, is just a '1000'. But that 4, if it were an ascii, it would be some writtable symbol, and it would be just a '1000'. The container is what brings meaning to the data inside. Data without contanier, raw data, is just bits.

Going up to the stack, again, you should think the same. THe abstraction IS the container, and is a container of CONTAINERS.

So something like a Stack<T> issomething like

_______________
|
| *top
| ==== type T==
| ==== type T==
| ==== type T==
|______________|

And then,after, those types T, or integers, or Strings, or whatever, will be containers that will hold some other bites in another precise way.

Is important to always talk about the abstraction, the box, because the implementation is totally dependant on system, language, compilation, cpu architecture... so, for as, they will always be boxes.

Coming to the stream, the stream is a little different than the others because the stream, in theory, only sends raw data and it only gets converted when you are gonna use it. This is true for IO Streams in Java, but not for the Streams concept itself, or Streams as in reactive programming, which are very different things. But, as a general simplification, the stream just sends the data crammed up, in a optimized way, and then you, or the stream, treats that data in the way needed for it to be understood when exiting it.

If you have any more questions, dont hesitate to ask

Every variable of non primitive type in Java is a pointer to an object.
An object of any type is an instance of a class. Whichever data type you are dealing with, in reality is just 1 single object. For example an ArrayList<String> li; it's NOT multiple strings, it is 1 object li of type ArrayList.

Having clarified that, A stream be it input or output is 1 object, i.e. a container. a stack is the same. In pretty much all programming languages, you can't have data without a container.

For all primitive types, of course, you must think of them as the data itself. For example an int a=3; you must think of a as 3 there is no container. This is because in Java you can't have a pointer to a primitive type.

Here is a short and hopefully helpful answer.

For all data types it should be "Containers"
Why ? - Because everything is an Object ( Encapsulation ) -
even an "int" is interchangeable with "Integer".

More Specifically

for FileIO -
Shape the containers as Pipes, so you can wrap them. Like this -
Image Link - https://i.stack.imgur.com/zRqoL.png

from Oreily Library itself -
https://www.oreilly.com/library/view/learning-java-4th/9781449372477/ch12s01.html

For Stacks - Containers shaped as boxes.
https://i.stack.imgur.com/JP7Dz.jpg

For Data Types - A Capsule is quite apt.
https://i.stack.imgur.com/Qqhrw.png

ref - https://stackify.com/oop-concept-for-beginners-what-is-encapsulation/

Hope that helped.

I like the allusions to familiar things (like stream of water or stack of books), it can be very helpful especially for beginners or general public. If that's your audience, feel free to add it to your description.

As for the stream, I'm fine with both with and without a container but I'd suggest to indicate stream direction.

As for the stack, I prefer it not having a container as a whole. More importantly, it's an organized pile with one item being clearly above another.

As for int, it doesn't need a container when being explained as a data type. (As soon as placed within a variable though, a 'container' would be appropriate, in my view).