code: public String getRealmName() {
          if (realmName == null || realmName.trim().equals("")) {
              realmName = getDefaultRealmName();
          }
          return realmName;
      }
docs: <p>
  Return the realm name. If the realm name set in <code>WSRealmNameCallbackImpl.setRealmName()</code>
  is <code>null</code>, then <code>null</code> is returned.
  </p>
  
  @return The realm name, could be <code>null</code>.