A COSMAC-based CHIP-8 emulator written in Java.
CHIP-8 is an interpreted language that was initially used in the RCA COSMAC VIP microcomputer, released in 1977. It was aimed to video games, and the COSMAC VIP shipped with 20 games, all programmed in CHIP-8. As such, this "emulator" is more of an interpreter, as it does not emulate real hardware. However, the CHIP-8 reference is quite similar to real hardware, but somewhat less complicated.
More information can be found here and here.
Javadocs can be found here.