I'm getting below error message when I try to drop a XDB tablespace in 9i.

ORA-29857: Domain Indexes and/or Secondary Objects Exist in TS

I'm getting below error message when I try to drop a EXAMPLE tablespace in 9i.

ORA-23515: materialized views and/or their indices exist in the tablespace

How can I drop these tablespaces?
I don't need to keep these tablespaces right?