SQL> alter tablespace java add datafile \'d:/programming/java.dbf\'; * ERROR at line 1: ORA-01537: cannot add file \'d:/programming/java.dbf\' - file already part of
Use like instead of =:
like
=
select TABLESPACE_NAME, FILE_NAME,STATUS from dba_data_files where UPPER(FILE_NAME) like '%JAVA.DBF';