Coffee GB v2.1.4 is released. Coffee GB is a Gameboy Color emulator written in Java 16 (core) and Kotlin (UI). It's meant to be a development exercise.

Features:
Full support for GB & GBC emulation.
Partial Super Gameboy emulation (borders and palette).
Cycle-exact CPU emulation. Each opcode is split into a few micro-operations (load value from memory, store it to register, etc.) and each micro-operation is run in a separate CPU cycle.
Quite compatible (all the Blargg's tests are passed, although some game still doesn't work)
Rollback-based netplay
MBC1-5 support
Battery saves
Support for zipped ROMs
ROM-based compatibility tests run from Maven

Coffee GB Changelog:
What's changed
Expand performance-mode batching across CPU, PPU, DMA, memory access, and peripherals, with additional state/replay regression coverage, diagnostics, and Android performance tooling.
Fix simultaneous 2P connections in Mach Go Go Go when the machines' timing phases differ. Each player still needs a saved car: complete a solo race and choose きろくする (Record) before entering 2P Battle.
Prevent competing Coffee GB processes sharing a Saves directory from freezing the host during netplay autosave handoff. All instances sharing Saves should use the updated version.
Restore GBVisualizer audio when skipping the boot ROM and initialize deterministic post-boot CPU, audio, palette, joypad, and DMA register defaults. Refresh state and replay baselines for these defaults; older SKIP boot-reference recordings may report divergence.
Merged pull requests
#668: Expand performance-mode batching and regression coverage — @trekawek.
#670: Fix simultaneous 2P connection in Mach Go Go Go — @trekawek.
#671: Prevent autosave races from freezing netplay connections — @trekawek.
#669: Initialize skipped-boot registers and fix GBVisualizer audio — @trekawek.
Fixed issues
#665: Fix the connection-time host freeze caused by shared-save autosave races, reported with Master Karateka.
#666: Fix Mach Go Go Go's simultaneous 2P connection failure.
#667: Restore missing GBVisualizer music with skipped boot.
Mach Go Go Go reaches course selection after the connection fix (#666).
Known platform limitations
On macOS, game controllers require a compatible system SDL2 installation; keyboard input and emulation remain usable without it.

Download: Coffee GB v2.1.4
Source: Here