If user's Profile has Read only access on Contact and OWDs(Org Wide Defaults) for Contact is Public Read only and there is a sharing rule which gives read write access to all contacts to that User's Role.In this case will User get Read/Write access to All Contacts ? I know Sharing rules are used against OWDs to open up sharing.Will Sharing rules overrides over Profile permissions ?
No. Sharing rules open up access to records. If the user's profile does not have edit on the contact object, he will not be able to edit the record.