Java Communication API

Java communication API is a software module (library) allowing Java application talk through serial port.

Java comm is a must for serial and parallel port support because Java "Virtual Machine" doesn't offer such a capability itself.
Instead, Sun made an extension (javax.comm.*) module and offered it for download, for Solaris/SPARC and Windows platforms only. No Linux, Mac OS, OS/2 support.

So, people started to write their own communication libraries. Most of it works as "plug-ins" for original Sun package and are compatible with applications written for that API.

On this page you'll find some info about various comm packages for Java. You can use them for your own software or for existing one, like gar2rnx / Java.

Java comm packages:

Installation notes:

I assume you're trying to use some kind of nonstandard configuration here. If you have standard PC with Windows and Sun Java Virtual Machine - just follow instructions for Sun package.

First, you should figure out whether package you downloaded works as Sun's package plug-in or as independent package.

If it works as a plug-in, you have to download original Sun package (most probably Solaris, not Windows version, but you should check your driver instruction for that).
Then, install Sun package by putting it's 3 files in three directories:

If your serial package works as package independent from Sun comm library, you should install it accordingly to instructions and remove Sun package from your system.
You should check whether your package implements standard javax.comm package like Sun. It can implement some other. For example, RXTX version 1.5 (currently in beta) implements "" instead of "javax.comm". So you have to change your application source code, from "import javax.comm.*" to "import*"

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For questions and fixes mail to MichalHobot(at)