How to compare that sequence of doubles are all “approximately equal” in Java?

Question

I have a method in java that returns a double number and I want to compare every double number that is returned every time I call the method(say 5 times), so that I can conclude

Answer 1

Approximate equality is defined in terms of the absolute difference: if an absolute difference does not exceed a certain, presumably small, number, then you can say that the values you are comparing are "close enough".

double diff = Math.abs(actual - expected);
if (diff < 1E-7) {
    // Numbers are close enough
}

You must be very careful to not confuse "close enough" end "equals", because the two are fundamentally different: equality is transitive (i.e. a==b and b==c together imply that a==c), while "close enough" is not transitive.