I am developing a java application using 64 bit eclipse on a 64 bit Windows 7 install. I’m forced to use a 32 bit JDK(1.7.0) because the application uses Jpcap, which wont compile with a 64 bit JDK.
The application has to be cross platform across 32 bit and 64 bit systems, which is normally the case with java applications developed using any JDK. But I believe the situation is slightly complicated because besides a jar, Jpcap installs system libraries (.dll/.so) which in turn are wrappers for WinPcap and libpcap. So a Jpcap call is a succession of nested invocations to these libraries.
Here’s the question:
Will the application executable work on 64 bit platforms? assuming users will have the required x86 libraries installed (jpcap.dll/.so, WinPcap, libpcap) as 64 bit versions do not exist for the windows libs.
You will need to use a 32-bit JRE to run the application. A 64-bit Hotspot JRE cannot use 32-bit native libraries.
But the flipside is that it doesn’t matter if you use a 64-bit or 32-bit Eclipse for developing and building … provided that you configure Eclipse to launch a 32-bit JRE for any testing that involves the native libraries.
And to be clear, you can run a 32-bit JRE on a 64-bit OS platform, but not the other way around.
UPDATE – apparently the jpcap.dll can be built for 64-bit Windows – see this posting: https://groups.google.com/forum/?fromgroups=#!topic/jpcap/-vxZv0eAcp4