if anybody facing this warring then follow this steps, this steps for stable RXTX-2.1-7 version
- Remove old librxtxSerial.so file from arm folder of jre installed in my BBB it is located under /usr/java/jre/lib/arm
- Download your rxtxSerial.so that suitable to your jre version from https://blogs.oracle.com/jtc/entry/serial_port_communication_for_java
- Copy it into arm folder of your installed jre in your BBB
- Rename it to librxtxSerial.so
- Start your java app, now you will get same version of java lib and native lib(my java lib version is RXTX-2.1-7)