Printing messages in the console working with SQL Developer is done in the following way:
- In the tab Dbms Output choose:

- Chose the connection:

- Running a small test:
DECLARE BEGIN DBMS_OUTPUT.PUT_LINE('boo'); END; /
Съответно нашия низ бива отпечатан в конзолните прозорци Script Output и Dbms Output:
anonymous block completed boo
