>> Can i reclaim the space?
Sure! There are many tools and techniques to reclaim space, and the Oracle segment advisor does it automatically:http://www.dba-oracle.com/t_reclaiming_disk_space.htm
Oracle has several tools to help reclaim disk space:
"alter database datafile xxx.dbf resize yym;" - This will remove space that the physical "end" if the datafile, and the command will not work if any segments extend beyond your resize boundary.
"alter tablespace xxx coalesce" - This command will reclaim space from honeycomb fragmentation
export-import - For a complete reorganization and space reclamation, export/import allows you to restructure your files and reclaim lost space.
dbms_redefinition - This procedure will reorganize a table while it remains online for updates.
"alter table xxx shrink"