tried using Java comm API on Linux platform 
When calling   CommPortIdentifier.getPortIdentifiers()
 got 
Caught java.lang.UnsatisfiedLinkError: no Serial in java.library.path while load

What do I have to do to make it work

Sorry but Java COMMAPI is currently only supported for Solaris/SPARC,
Microsoft Windows and Solaris/x86. That's why you are having an
UnsatisfiedLinkError, which is an exception related with native
libraries (such as COMMAPI). You don't have much to do other than
waiting for Sun to release a version for Linux. Alternatively you can
try your chance with a third party COMM driver such as JCL (Java Comm
for Linux):

http://www.geeksville.com/~kevinh/linuxcomm.html

Regards
Bio
Google Answers Researcher

Hi,

My answer is, in reality, a development from Bio's comment and keeps
my Java knowledge base from vegetating. Unlike Bio, my installation
experience is Windows Java, my Linux Java experience coming
pre-configured. My Java comms experience is a Socket-based chatroom
Protocol, Server and Client window allowing HTML tags.


* An identical question thread to yours is located on Sun at -

 http://forum.java.sun.com/thread.jsp?forum=8&thread=175806

* Most up-to-date Linux Java Serial-Programming "patches" are -

http://www.rxtx.org/download.html
http://www.geeksville.com/~kevinh/linuxcomm.html (this code is
contained within the RXTX distribution)

* The following should assist in "patching" your Linux installation -

http://wass.homelinux.net/howtos/Comm_How-To.shtml
http://www.apms.com.au/tini/javakit.html (The TINI JavaKit itself is
unrelated)

* For other Linux Java Serial-Programming HOWTOs see -

http://www.mail-archive.com/cgi-bin/htsearch?config=java-linux_java_blackdown_org&restrict=&exclude=&words=CommAPI
[or RXTX]
://www.google.com/search?q=Linux+serial+CommAPI [or RXTX]

* For CommAPI (javax.comm) Serial-Programming in general -

http://pharos.inria.fr/Java/query.jsp?cids=c_2071&sort=title
http://sourceforge.net/projects/jcomm (an example full project)


Please donate your $50 tag to a Christian org instead, for instance
www.barnabasfund.org/donations.htm

Thanks,
Mark F
GB


My Ref: Serial Port usage in Java
http://answers.google.com/answers/main?cmd=threadview&id=208382

Hi leonidbash-ga,

You do not have native libraries to access the comm port through your
Java application.

You may want to download linux based libraries from
http://www.rxtx.org

They have clear instructions on how to use the comm API in linux. The
comm api has become gnu.io package in the latest version of rxtx
libraries. You may have to replace java.comm.* with gnu.io.*

Let me know if it works for you.

Regards
ldavinci-ga

You should be able to access the serial ports by reading and writing
to /dev/ttyS* from within Java.

The difficult part would be configuring the serial port before using
it, but you the "setserial" command will to do that.