Does volatile influence non-volatile variables?

Question

Okay, suppose I have a bunch of variables, one of them declared volatile:

int a;
int b;
int c;
volatile int v;

If one thread writes to all four

Answer 1

Yes. volatile, locks, etc., setup the happens-before relationship, but it affects all variables (in the new Java Memory Model (JMM) from Java SE 5/JDK 1.4). Kind of makes it useful for non-primitive volatiles...