title: oracle does not display output - anonymous block completed
body: <p>I'm trying to display a message in oracle sql develper on oracle 11g.
  Straight from the doc:
  <a href="http://www.oracle.com/technetwork/issue-archive/2011/11-mar/o21plsql-242570.html" rel="nofollow">http://www.oracle.com/technetwork/issue-archive/2011/11-mar/o21plsql-242570.html</a></p>
  
  <pre><code>DECLARE
    l_message  
    VARCHAR2 (100) := 'Hello World!';
  BEGIN
    DBMS_OUTPUT.put_line (l_message);
  END;
  </code></pre>
  
  <p>gives me a message:</p>
  
  <blockquote>
    <p>anonymous block completed</p>
  </blockquote>
  
  <p>why?</p>