Yes, It is Obsolete as far as I know and not supported by linux. Was it
ever supported in some older kernel at all that you mension rh9 (2.6/2.4
kernel? ), or it is first linux port  iteration try?

Try alternative handshaking for inserting waits in communication with
slow devices in your java  code.

If you don't want to change your java code, you should adjust your
native code behaviour, overriding the device-drivers, (userspace
alternatives?) .
All these will be native solutions anyway when your java code can not be
modified, with a fair amount of labor.