We share our limited Java knowledge and on top of that my knowledge of the Chinese language in the referenced library is really zero ?. But where would we be without Google (translate) ?.
You refer to SerialLibJab.jar which sets the serial port to allow serial communication between two serial ports.
The serial port on your unnamed device has a UART, to which one or more commands must be sent so that communication is possible with your unknown unnamed device. Those commands are different for each UART. Anyway you have to use a library for this to solve that challenge. Two possibilities either you have the source of the library, or at least you have the jar of that library.
A library that probably looks like it won't help us, but we need the 2nd jar and/or AAR file or its current source which is now throwing the error. I want to try to run it through a compiler with Android API 33 to see what errors and invalid routines to pick out and fix. Can post the missing jar/aar/source to the forum?