Why no output when PLSQL Anonymous block completes? [duplicate]

Answer 1

Viewing the DBMS_OUTPUT depends on the program.

SQL*Plus and Oracle SQL Developer

Run SET SERVEROUTPUT ON; first. This is all that's necessary in SQL*Plus or recent versions of Oracle SQL Developer.

SET SERVEROUTPUT ON;
begin
    dbms_output.put_line('Testing output');
end;
/

PL/SQL Developer

Output is automatically detected and displayed in the "Output" tab.