What programming technique is this?

I have two Java classes. The first one is called “Index”, and the second one, temporarily, I called it “IndexCache”:

What programming technique is this?

I have two Java classes. The first one is called “Index”, and the second one, temporarily, I called it “IndexCache”:

Domain analysis – why OFF points are inside of the domain when the border is open

I have asked on a few other sites, no response but it must be something silly as many authors mention in their books.

Domain analysis – why OFF points are inside of the domain when the border is open

I have asked on a few other sites, no response but it must be something silly as many authors mention in their books.

Domain analysis – why OFF points are inside of the domain when the border is open

I have asked on a few other sites, no response but it must be something silly as many authors mention in their books.

Domain analysis – why OFF points are inside of the domain when the border is open

I have asked on a few other sites, no response but it must be something silly as many authors mention in their books.

Domain analysis – why OFF points are inside of the domain when the border is open

I have asked on a few other sites, no response but it must be something silly as many authors mention in their books.

Domain analysis for discrete values – ON and OFF points in these cases

Following my previous question (with great answer from Bart van Ingen Schenau), I noticed a discrepancy I could not wrap my head around:

Domain analysis for discrete values – ON and OFF points in these cases

Following my previous question (with great answer from Bart van Ingen Schenau), I noticed a discrepancy I could not wrap my head around:

Domain analysis for discrete values – ON and OFF points in these cases

Following my previous question (with great answer from Bart van Ingen Schenau), I noticed a discrepancy I could not wrap my head around: