docs: @Override
      public Object getObjectInstance(Object o, Name n, Context c, Hashtable<?, ?> envmt) throws Exception {
          // by OSGi JNDI spec Name and Context should be null
          // if they are not then this code is being called in
          // the wrong way
          if (n != null || c != null)
              return null;
          // Object is String, String[] or null
          // Hashtable contains any environment properties
          if (o == null) {
              return new JavaURLContext(envmt, helperServices);
          } else if (o instanceof String) {
              return new JavaURLContext(envmt, helperServices).lookup((String) o);
          } else {
              throw new OperationNotSupportedException();
          }
      }