Does GL E750 identify FT232 USB-Serial chip automatically?

I wanna read the data of the RS422 serial device which was connected with GL E750 by a USB2RS422 cable.

You should install kmod-usb-serial-ftdi

like this ?

Yes you are right.

Yes

does E750 also support those programming languages such as : C/Python ? support SSH login ?
support Java ?

C and Python are OK. Ssh is ok.

No Java.