Because, well, it's there, I was trying to build jdk9 from source and got an entertaining failure.
Error: time is more than 10 years from present: 1420063200000
java.lang.RuntimeException: time is more than 10 years from present: 1420063200000
What it's doing here is generating currency data, and there's a sanity check that the data's reasonably up to date. (It only tripped over that 10 year threshold about a month ago.)
Ho hum. Sledgehammer time.