java.util.Timer not handling negative System.currentTimeMillis()

Fri Nov 25 16:06:00 GMT 2005

Martin Egholm Nielsen writes:
 > > > I just encountered a funny (initially strange) problem arising because 
 > > > my embedded RT-Clock was set to the year 1909.
 > > > Hence System.currentTimeMillis() returns a negative number, and this is 
 > > > used internally in java.util.Timer#schedule(), and throws an unchecked 
 > > > exception - aarghh...
 > > > 
 > > > I know this is an obscure problem, but is there is requirement that we 
 > > > are only "allowed" to run gcj on targets with clocks > 1970.
 > > > One could change the Timer code to handle this situation, or just ignore it.
 > > > 
 > > > For now I will just make sure the time is not less than 1970 and larger 
 > > > than some other limit overflowing the long.
 > > > 
 > > > The problem arises because my target's RTC comes with an undefinded 
 > > > initial time - hence anything is possible :-)
 > > 
 > > This is a tricky one, because even if we fix gcj to allow this I
 > > suspect some user code will be confused. It is perhaps not
 > > unreasonable for a programmer to assume that the "current time" during
 > > a program's execution will not predate her birth!
 > > 
 > > You need to make sure that your RTC is initialized to some sane value.
 >
 > Now, that's the hole key issue: "Sane" is not necessarily 1970+ for one 
 > that doesn't bother about the absolute time, but just wants to do 
 > something in relative time...
"Sane" in this context just means > 1970. If you want to work in
relative time, start at 1970.
Andrew.