Question: How do i delete all the tables in the schema on Apache Derby DB using JDBC?

Answer: 
I think most db providers don't allow DROP TABLE \* (or similar).

I think the best way would be to SHOW TABLES and then go through each deleting in a loop via a resultset.

HTH.
Download Squirrel SQL from <http://squirrel-sql.sourceforge.net/>

Connect to the database.

Expand the TABLE node.

Select the tables that you want to drop.

Right click and select -> Scripts -> Drop table scripts

Run the generated queries

You can even select delete records to empty the selected tables.