CREATE OR REPLACE PACKAGE TEST_PKG IS
MyInstance varchar2(50);
PROCEDURE proc_test;
END TEST_PKG;
/
 
CREATE OR REPLACE PACKAGE BODY TEST_PKG IS
 
PROCEDURE proc_test is
BEGIN
  SELECT instance_name INTO MyInstance from v$instance ;
  dbms_output.put_line('Your instance name is: ' || MyInstance ) ;
EXCEPTION
  WHEN NO_DATA_FOUND THEN
    dbms_output.put_line('No Instance Name found') ;
END proc_test;    
END TEST_PKG;
/
 
set serverout on
exec TEST_PKG.proc_test;