EXCEPTION
WHEN OTHERS
THEN
DBMS_OUTPUT.put_line (SQLERRM);
DBMS_OUTPUT.put_line (' ');

sir quotas should ask at runtime for each tablespace, so user can specify quotas as per the requirements.

our requirement is to create tablepaace and users outside the SQL*PLUS, so that the user can not touch the production database. the above code is working perfectly but i cannot able to specify quota for each tablespace which are in the TablespaceNames.txt. it ll asks quotas size for only one time, whatever user specify it is applying that quota size to all tablespaces names which are in utl-file. but i need to apply quota size differently for each tablespace.

orclz>
orclz> begin
  2  EXECUTE IMMEDIATE 'create user &&username identified by &&password default tablespace &&default_tablespace temporary tablespace &&temp_tablespace';
  3  end;
  4  /
Enter value for username: jw
Enter value for password: jw
Enter value for default_tablespace: users
Enter value for temp_tablespace: temp quota unlimited on system
old   2: EXECUTE IMMEDIATE 'create user &&username identified by &&password default tablespace &&default_tablespace temporary tabl
espace &&temp_tablespace';
new   2: EXECUTE IMMEDIATE 'create user jw identified by jw default tablespace users temporary tablespace temp quota unlimited on
system';

PL/SQL procedure successfully completed.

orclz>
 

This is the way SQL*Plus (or other SQL client tool) works.
It asks for the values then send the PL/SQL block to the server to be executed.
As I said you have to put the quota in the file or in another file.
Or if you want to do it at client side then write your own code.

Note that:

1/ "revoke unlimited tablespace from &&username" is useless as your grant it DBA and so it implicitely has UNLIMITED tablespace even if you don't see it.
2/ So "alter user &&username quota &&quota_size on ' || objTablespace(i)" is useless as user has unlimited quota on all tablespaces.
3/ So your problem is "solved" as you don't need to ask for a quota.