Security: Unix versus Windows

We all know that most operating systems and software suffer from identical 
flaws no matter what their origin and dev model is. Whatever can be said in 
favour of one development model can equally be argued against it. For example 
the fact that Windows is closed source means joe avg can't audit the source 
for vulnerabilities to fix them while at the same time joe avg can't audit 
the source for vulnerabilities to exploit them. And this single point can be 
argued to great depth and always ends in one side questioning the other sides 
understanding of the subject matter.

My personal belief is that the open source development model is superior to 
closed source equivalents including microsofts on many fronts including 
security. But I am an open source jesuit and the debate is so religiously 
controversial it is like the marihuana debate where one half claims it's 
harmless if not healthy and the other claims it's harmful and dangerous. 
Studies are always biased, reality is never objective and the debate could 
have been engendered by the jesuites.

And never shall the twain meet. I'm not at all sure if the discussion we are 
having here is worth having anymore. 

How about what Bill Joy Co fouder of Sun had to say about C though?
http://www.interesting-people.org/archives/interesting-people/200310/msg00034.html

quote "You have to find a way to structure your systems in a safer 
way. Writing everything in Java [a programming language created by Sun] 
will help, because stuff written in antique programming languages like C [a 
widely used language created by Bell Labs in the early 1970s] is full of 
holes. Those languages weren't designed for writing distributed programs to 
be used over a network. Yet that's what Microsoft still uses. But even Java 
doesn't prevent people from making stupid mistakes."

To what degree does Java lean on libraries that have been written in C though?