Physical affection is commonly expressed between members of the same gender:

Boys (or men) together, or girls (or women) together commonly walk along arm in arm or hand in hand. Or, the more elegant 'hand on the crook of the elbow' hold is used, generally practiced by more mature women. It would be natural to think that this is certainly a non-homophobic society for all of these displays of same-sex affection, but in fact China considers homosexuality a crime. So if you see people of the same sex walking hand in hand or hanging on each other, it does not mean they are lovers, it just means they are observing their cultural right to express same-sex affection. Or, they are hanging onto each other so that they don't get lost in a crowd.