I noticed in the test code linked to by the article that the closed over variables are all declared final. I'm not sure if that's just because of the early stage of implementation or if that's actually going to be a requirement. If so that seems unfortunate and maybe an impediment to interoperability.
Closing only over final variables is deliberately a requirement because closing over non-final variables can lead to confusing situations. I discussed this in more detail in a previous thread:
