According to a statement in the book The Well-Grounded Java Developer , the Java Virtual Machine—which is that incredibly nifty piece of software that allows applications written in the Java programming language and others to run on many different types of operating systems, such as Windows, Mac OSX, Linux, etc.—represents approximately “1,000 person-years of effort”. The book was published in mid-2012, which was more than three years ago now, so that number would already be significantly higher.

Let’s do some simple arithmetic:

y = ( number of years )
d = ( number of days per year )
h = ( number of hours per day )
t = ( total number of hours )

t = y * d * h

y = 10 yr
d = 365 day/yr
h = 24 hr/day

t = ( 10 yr ) * ( 365 day/yr ) * ( 24 hr/day )

t = 8,760,000 hr

Assuming that a standard year’s worth of work is comprised of 2,000 hours of labor—and I feel obliged to point out that this is a number at which some people would scoff—it would take one person 4,380 years to match the amount of time that was committed to this technology back when those words were put into print.

On a somewhat related note, I find it interesting that the authors chose the term “person-years”, as if the fellows on the Java team are something other than human. Perhaps I’m reading into this too much, but it may suggest that the Java Virtual Machine was made by aliens… or dogs… or maybe very intelligent hamsters?