Please see IMPORTANT comments about the Release field in the Customer Call Information.

1. Use green thread JDK1.1.4 from JavaSoft :

When using recvfrom in a native method, it blocks even though
it has been set to "non blocking". If the same routine is
called from a C program, it works fine. However, as I said, when called
from a Java program it works incorrectly. see BUG 4092593. Also
attached the test program from BUG 4092593 says how to reproduce
this bug.

2. The following is for information only :
   Use Java1.1.3 & Java1.1.4 from Sunsoft (native thread only)

we have a C++ (devpro,v4.2) library (not MT safe, not multi-threaded), The library has a UDP socket being set to non-blocking mode, when that function/method being called through RMI-->JNI (i.e. the implementation of the
interface has JNI interface), the recvfrom() on that socket returns
IMMEDIATELY with the global errno = 2, it means :

#define ENOENT 2 /* No such file or directory */

The above is just for information only as we use a not MT safe, not multi-thread
lib in the native thread Java. not sure if it is a requirement to use MT safe, multi-threaded lib in Java native thread environment.