Python vs Java garbage collection?

["Martin v. Löwis"]

Bengt Richter wrote:
> E.g., suppose you had a suite-introducer whose purpose it was to define
> a local block of statements like try/finally but so that the compiler
> would automatically generate code so that all bindings created within
> the suite would be monitored and and immediately (i.e., maybe even
> during expression evaluation, but at least at the end of a statement)
> finalized when the equivalent of ref count going to zero happened. E.g.,
> 	autofinalize:
>             s = file('foo').read()

How would you implement this in Jython? In particular, what would be the 
equivalent of ref count, and how could you tell it goes to zero?

Regards,
Martin