Testing with USB-UART PL2303 and YS-IRTM
First connect PL2303 to PC USB port, download and install correct driver for Windows 10. If you have problems with installation, try install previous veersion.
After seccessfully installation start Genymotion and run your android emulator. Open Virtual Box and start virtual machine which associated with your android Genymotion emulator and connect PL2303 adapter to virtual system.
Now you can start Intellij Idea and create new android application for test communication. Examples with source code you can find on GitHub. Start debug button.
Press buttons for communication.
You can see how its work on this video: