Oracle 11g exp cannot export empty tables

Since the company does not have Oracle 11g, and has never used this version before, some new features are not very familiar. This export of the database of 11 GB encountered the problem that exp could not export an empty table. After a long time, I did not understand it. Later, I switched to the Data Pump Mode of expdp and added the version parameter, easy to import to 10 Gb database, and finally completely export the database, including 100 multi-empty tables.
 
I learned online today that this exp is a new feature of 11 GB without exporting empty tables. When there is no data in the table, no segment is allocated to save space. So when exp is exported, do not export these tables.
 
There is a convenient solution to this problem on the Internet.
 
Use the following statement to search for an empty table and generate an execution command.
Select 'alter table' | table_name | 'allocate extent; 'from user_tables where num_rows = 0;
 
Export the query results and execute the Export Statement.
Similar to alter table T_TAB allocate extent;
 
Then, use exp to export the database, and finally completely export the database including the empty table.