Hi,
The easiest way to create bitcoin is by using the Solidity programming language which has a script similar to Java or using Serpent which has Python like script. You can also use ready made scripts that are available for POS / POW. But remain aware about the security.
After giving it a lot of thought, I decided to use Python. GIL thread concurrency is sufficient. Mining might suffer, but can be replaced with a C mining module. Most importantly, code will be easier to read for open source contributors and will be heavily unit tested. Using frozen pip dependencies, virtualenv, and vagrant or docker, we can fire this up fairly easily under any operating system.
Regards,
Mit-