Z64K (2019/06/13) 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 Changelog:
13 June
Added 64K EF cartridge support for Atari 2600
Fixed bug that didn't set correct bank selection registers for ROMS with 3 x 4K ROMS. Updated RAM size detection code for SC to detect variable RAM sizes. FA (RAM Plus) cartridges work now.
12 June
Fixed colour priority of TIA playfield in score mode.
Allow loading of .a26 file extension.
Fix minor bug with TIA RESP timing. 32 text demo show correct spacing for all rows now.
Slightly improved TIA NUSIZ register behaviour when updatedduring draw

http://www.z64k.com/

http://www.emucr.com/2019/06/z64k-20190613.html