IMAVR is Atmel AVR 8-bit RISC chip emulator for UNIX. You can run your code before programming to chip. Embedded simple debugger and disassembler. Emulate wide range of AVR chip, wide range of their modules: EEPROM,USART, timers and so on.
JTools.Ruby is easy way to access Java 2 class-files via scripts written in Ruby language. There are class-file disassembler, assembler and simple Ruby to Java bytecode compiler. The work is at the start point.