My hub is on Ethernet network,does it mean hub has IP Addr?

[michel]

Hubs are ethernet devices - not IP devices. They have no IP addresses because they don't handle network layer protocols. They only handle the physical layer.
Network architectures are broken down into layers. The model for these layers is called the OSI model. Not all networking protocols directly relate to the OSI model, but it's usefull when describing the way that a network model functions.

[joe]

Since hubs and switches are on the physical and data link layer they are unaware of the network layer that IP uses. Managed switches have an IP address, but this has nothing to do with the function of the switch - it's a seperate part of the switch that provides a management interface.