How to print to CUPS (running on another computer in the LAN)? How to print from Android to CUPS (running on another computer in the LAN)?

(CUPS (Common Unix Printing System/Server) is of course already set up to accept requests over the LAN.)

Preferably, without relying on proprietary software.
I have recently released an Android app based on (a modified) version of Cups4J. Communication is via http/https. The main thing I had to/opted to change from the java library was a dependency on JAXB for XML processing (a. I felt it too heavy b. Android does not have this javax lib and importing it apparently involves repackaging) relying instead on some hard coding.  

Download Android CUPS Printing on the Play Store or get the sources on GitHub.