X86 vs x64 socket issue

Question

I created a program to read data from a MulticastSocket and if I run the application explicitly with the x86 version of Java, I have no issues. However, if I run it explicitly with the x64 version, my application starts fine, but I read no data.
Anyone have any idea as to why this would be the case? I know Java should compile both versions to the same byte code, but just to be sure, I compiled with the x64 javac and ran with the x64 java and still nothing. Again, x86 version works fine so it isn't a firewall issue. It didn't work on my 1.6.0_07(x86) and 1.6.0_10(x64) that were installed so to make sure it wasn't a modified path issue, I uninstalled both and installed the x86 and x64 JDKs for 1.6.0_13 and still the same issues.
Any help would be appreciated.
Stephen

Answer 1

sranger wrote:
Well, after some testing, it seems that the while(!ready) {} loop I was doingWas that loop literaly like this:
while (!ready) {
  // do nothing
}? If so, then you have two problems:
1.) It's very bad form to do busy waiting (that's what it's called). It wastes CPU time and is generally not a good idea
2.) If "ready" is not declared volatile, then the JVM is perfectly free to optimize away all but the first read accesses to "ready". This way it will never notice if the value changes.
while waiting for a UI element to be created will give the UI element CPU time if running as 32bit but if ran as 64bit, everything stalls.This sounds exactly as if "ready" is not volatile and the 32bit JVM optimized slightly different than the 64bit one.
I added a Thread.sleep(0); in the loop and it started working.A nasty hack. Replace it with a "real" fix, if at all possible.