Just to review, you did actually check that the TEST is failing with a print as opposed to just failing to observe a
change in the vector? Note that if you don't commit the changes I'm not sure they persist ( among other things that could
go wrong, depending on how you really checked this). So, if you ran the code, cycled the power, and didn't find a change in your
vector and concluded the test failed, you may want to break it up into smaller pieces 
Additionally,
1) AFAIK java doesn't normally inline except maybe for hotspot. So, rather than make repeated calls to const accessor results, just make short temps on the stack ie long date1=foo.datemaker(); This also helps avoid flakely inconsistencies when you make multiple
calls to currentTimeMillis() and expect them all to be the same
2) Also, you should have't to cast (long) for the accessors.
3) Avoid holding any locks when you call IO or "unknown" code of anykind, including innocuous System.out.println(). Probably not a big deal but
just avoids problems later if these statements are intended to be permanent. usually you can just synchronize around some safe short
piece of code to set flags, making mutexes or semaphores, etc
http://java.sun.com/developer/technicalArticles/J2
( fwiw, my own code is littered with examples of the type you use, I'm just suggesting this for reference).
4) If you realy mean 2 days rather than 48 hours, sure you have to remove some remainders etc.
