A zarf is a sort of cup exoskeleton with a handle, that fits around a finjan, or handleless Turkish coffee cup. The "java jacket" could be thought of as a descendent of the zarf; it lets you hold your coffee cup without burning your fingers.
The zarf is usually metal, though they were also made of wood or ivory. Ottoman-era zarfs can be fabulously ornate and expensive, and are much sought after by collectors.
Project ZARF is also the code name for the Air Force's tiger team that cracked MULTICS security in the mid-1970s. The Air Force had picked up the word "zarf" as slang for the brown plastic holders for disposable coffee cups.