It is evident from the documentation that a space will have a displayName only if it is of type ROOM.
Reference: https://developers.google.com/hangouts/chat/reference/rest/v1/spaces#Space
However sometimes I receive the addedToSpace event request from hangouts chat without a displayName in the space object, even if the space type is a ROOM.
Is that in any way possible? Please help me out !
Found the Answer guys. If the room is a group, then there will be no display name for the same. Hence no display name is available. However, the group members are not sent via the request. Anyways, Thank you all for your help.