> The perfect Java replacement would have - local type inference, less verbosity (e.g. public by default), full closures, anonymous blocks, no generics, special syntax for arrays and hashes, operator overloading and the ability of a variable to behave as if dynamic (e.g. leveraging the future InvokeDynamic). I would also completely purge checked exceptions and also get rid of the general syntax for anonymous classes - basically get rid of anything not useful.

Ahem. http://groovy.codehaus.org/

The #1 feature of Groovy in my mind is that there is almost no learning curve whatsoever. All Java code is already Groovy code - you can learn all the dynamic tricks as you go.