Introducing the concepts of Object/Properties/Methods

[euu2021]

As discussed during the meeting, I created a draft for an explanation of the concept of Object/Properties/Methods in Java.

This section is in the middle of the sequence of explanations, so the user will already have learned some things. I will explain better how it fits in the sequence in the thread about the new structure of the documentation. Here, I just wanted to complete what I tried to explain during the meeting.

Note that I have in mind people who never wrote a line of code in their lives. So, I tried to make it simple and objective, touching only the concepts that will be used in this section. On the internet, I found excellent explanations, but they usually explain also other concepts, like class and encapsulation. For example, I liked a lot this explanation from the Oracle documentation, but it would bring unnecessary complications at this moment.

I checked several sources on the internet, so I think this simplification is not (a lot) incorrect. But, I'm an amateur, so please correct me if my understanding of the concepts is imprecise.

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About the terminology "attributesXproperties": I see it being used interchangeably on the internet (and also in our documentation). I suggest using properties, because attributes already have an important and different meaning in FP.