JAVA- PLSQL STORED PROCEDURES

How can I protect my PL/SQL source code?

PL/SQL V2.2, available with Oracle7.2, implements a binary wrapper for PL/SQL programs to protect the source code.
This is done via a standalone utility that transforms the PL/SQL source code into portable binary object code (somewhat larger than the original).
This way you can distribute software without having to worry about exposing your proprietary algorithms and methods.
SQL*Plus and SQL*DBA will still understand and know how to execute such scripts. Just be careful, there is no "decode" command available.

The syntax is: wrap iname=myscript.sql oname=xxxx.plb

Can one print to the screen from PL/SQL?

One can use the DBMS_OUTPUT package to write information to an output buffer. This buffer can be displayed on the screen from SQL*Plus if you issue the SET SERVEROUTPUT ON; command.

For example:
set serveroutput on
Begin
dbms_output.put_line('Look Ma, I can print from PL/SQL!!!');
end;
/

DBMS_OUTPUT is useful for debugging PL/SQL programs. However, if you print too much, the output buffer will overflow.

In that case, set the buffer size to a larger value,

Eg.:
set serveroutput on size 200000

If you forget to set serveroutput on type SET SERVEROUTPUT ON once you remember, and then EXEC NULL;.

If you haven't cleared the DBMS_OUTPUT buffer with the
disable
or
enable procedure,
SQL*Plus will display the entire contents of the buffer when it executes this dummy PL/SQL block.