Meaning of Double.doubleToLongBits(x)

Question

I am writing a class Vec2D, representing a 2 dimensional vector. I store x and y in doubles.

When asked to genera

Answer 1

A quick glance at the online javadoc yields this:

Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout.

...

In all cases, the result is a long integer that, when given to the longBitsToDouble(long) method, will produce a floating-point value the same as the argument to doubleToLongBits (except all NaN values are collapsed to a single "canonical" NaN value).

So it's probably a way of standardizing the double representations of x and y, as NaN can have multiple double representations