Virtual Judge is not a real online judge. It can grab problems from other regular online judges and simulate submissions to other online judges.
It aims to enable holding contests when you don't have the test data.
Currently, this system supports the following online judges:
ACdream
Aizu
CFGym
CSU
FZU
HDU
HUST
HYSBZ
LOCAL
NBUT
POJ
SCU
SGU
SPOJ
Tyvj
UESTC
URAL
UVA
ZOJ