Removing user-created datafile from SYSTEM tablespace in Oracle

Question

While attempting to create a replacement tablespace for USER, I accidentally created a datafile in SYSTEM

Too many applications are using the database to bring down the entire database, and people will get hurt if these applications are not running.

Is there a way for me to remove the datafiles from the SYSTEM tablespace without bringing it down?

I tried:

ALTER TABLESPACE SYSTEM DROP DATAFILE 'path_here.dbf'

but get this error:

Error starting at line 1 in command:
alter tablespace system drop datafile 'path_here.dbf'
Error report:
SQL Error: ORA-01541: system tablespace cannot be brought offline; shut down if necessary
01541. 00000 -  "system tablespace cannot be brought offline; shut down if necessary"
*Cause:    Tried to bring system tablespace offline
*Action:   Shutdown if necessary to do recovery

Answer 1

From the Oracle 11.1 documentation

You cannot drop datafiles in the SYSTEM tablespace.

However you can resize data files.