CommPortIdentifier (discovers and names ports like /dev/ttya or COM1 ) and CommPort (abstracts the port and manages InputStream / OutputStream ).
Oracle/Sun dropped support for the original JavaComm API years ago, making it hard to find official downloads. Package Javax Comm
While it was once a stable and flexible solution for Java-to-hardware communication, javax.comm should be avoided for new projects . It is extremely difficult to set up on modern systems, and superior, actively maintained libraries are readily available. It is extremely difficult to set up on
Uses a Java event model to detect changes in signal lines (e.g., carrier detect). Review & Status (As of 2026) It has known limitations with 64-bit Windows and
It can be notoriously difficult to configure, often requiring precise placement of javax.comm.properties . It has known limitations with 64-bit Windows and is not truly cross-platform without bundling separate native libraries for each target system.
The de facto standard replacement for many years was RXTX (e.g., org.rxtx:rxtxcomm ), but it is also considered old. Modern Java serial communication is typically handled via modern, maintained libraries like jSerialComm or jSSC (Java Simple Serial Connector).