RXTX is a Java library providing serial and parallel port communication.

RXTX's .info file says it requires the jdk package, but other JDKs can
be used instead (e.g. openjdk8, adoptopenjdk).

If you are upgrading from rxtx-2.0_7pre2, please note that the javacomm
package is no longer required and should be uninstalled before building
rxtx-2.2pre2.