In Java, are static class members shared among programs?

Question

I imagine that no, they aren\'t, because every process has its own memory space, of course.

But how does the whole JVM thing actually work? Is there

Answer 1

No, static variables aren't between JVMs. Yes, there's a separate JVM process for each Java app you run.

In some implementations I believe they may share some resources (e.g. memory for JITted code of JRE classes) but I'm not sure. I believe there's ongoing work to enable more sharing, but still in a robust way. (You don't really want one JVM crashing to affect others.)

No, you can't make programs share variables transparently.

I believe there are books about the JVM, but I can't recommend any. You'd probably be best off looking for HotSpot white papers for details of that. This one is a pretty good starting point.