title: DBMS OUTPUT PUT doesn't print anything
body: <p>I'm new to PL/SQL and I want to show the following message.
  When I compile it in SQL Developer I only get</p>
  
  <pre><code>  PL/SQL procedure successfully completed.
  </code></pre>
  
  <p>My code is this:</p>
  
  <pre><code>SET SERVEROUTPUT ON;
  
  DECLARE
    mesaj VARCHAR2 (100) := 'PL/SQL';
  BEGIN
    DBMS_OUTPUT.PUT(mesaj);
  END;
  /
  </code></pre>