code: public static void addProperty(Stanza packet, String name, Object value) {
          JivePropertiesExtension jpe = (JivePropertiesExtension) packet.getExtension(JivePropertiesExtension.NAMESPACE);
          if (jpe == null) {
              jpe = new JivePropertiesExtension();
              packet.addExtension(jpe);
          }
          jpe.setProperty(name, value);
      }
docs: Convenience method to add a property to a packet.
  
  @param packet the stanza to add the property to.
  @param name the name of the property to add.
  @param value the value of the property to add.