[dasyatidprime]

It's possible to use a type parameter in a throws clause in Java, last I checked (as I also mentioned in more detail above). But it doesn't seem to be common practice, so interop is still a disaster.

[Quekid5]

That only works up to one checked exception type, because Java doesn't have anonymous union types.

It really is a lose-lose unless Java grows a more powerful system around this.