title: Why do I have these warnings with Jena 2.11.0?
body: <p>I am using Eclipse and Java. I've setup the jena library and done my first RDF statement using this library, but I get a warning and I don't know exactly what it means.
  This is the code:</p>
  
  <pre><code>import com.hp.hpl.jena.datatypes.xsd.XSDDatatype;
  import com.hp.hpl.jena.rdf.model.Model;
  import com.hp.hpl.jena.rdf.model.ModelFactory;
  import com.hp.hpl.jena.rdf.model.Property;
  import com.hp.hpl.jena.rdf.model.Resource;
  
  public class Main {
  
      public static void main(String[] args) {
          Model m = ModelFactory.createDefaultModel();
          String NS = "http://www.example.org/rdf/";
          Resource r = m.createResource(NS + "r");
          Property p = m.createProperty(NS + "p");
          r.addProperty(p, "hello world", XSDDatatype.XSDstring);
          m.write(System.out, "Turtle");
      }
  
  }
  </code></pre>
  
  <p>And this is the output:</p>
  
  <pre><code>log4j:WARN No appenders could be found for logger (org.apache.jena.riot.stream.JenaIOEnvironment).
  log4j:WARN Please initialize the log4j system properly.
  log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
  &lt;http://www.example.org/rdf/r&gt;
          &lt;http://www.example.org/rdf/p&gt;  "hello world"^^&lt;http://www.w3.org/2001/XMLSchema#string&gt; .
  </code></pre>
  
  <p>So the code does compile and work but I don't know what to do about this warning.
  How can I get rid of it?</p>