Z64K Beta (2017/12/04) is released. Pixel exact emulation of the Commodore 64, VIC 20 and Atari 2600 written entirely in Java. The emulators should run on any platform with an updated java runtime environment installed.

Z64K Beta Changelog:
Added ability to select custom ROMs. (see 9 October for link and more info)

Download: C128 Beta (2017/12/04)
Download: C64 Beta (2017/12/04)
Download: VIC20 Beta (2017/10/24)
Download: Atari2600 Beta (2017/10/24)
Source:Here