The atg.commercecsr.returns.ReturnTools.createReturnShippingGroupInstance
(ShippingGroup) method creates a return shipping group instance based on the returnShippingTypeClassMap property value. If a shipping group type is configured with a ReturnShippingGroup class, a return shipping group instance is created. If not, a default value instance is created. This method calls the ReturnShippingGroup(ShippingGroup) constructor to load ReturnItems.

The default configuration for the returnShippingTypeClassMap property is:

/atg/commerce/custsvc/returns/ReturnTools.properties
returnShippingTypeClassMap=\
        default=atg.commerce.csr.returns.ReturnShippingGroup,\
        hardgoodShippingGroup=atg.commerce.csr.returns.ReturnShippingGroup