code: public final Object getObject(String key) {
          ResourceBundle last, theParent = this;
          do {
              Object result = theParent.handleGetObject(key);
              if (result != null) {
                  return result;
              }
              last = theParent;
              theParent = theParent.parent;
          } while (theParent != null);
          throw missingResourceException(last.getClass().getName(), key);
      }
docs: Returns the named resource from this {@code ResourceBundle}. If the resource
  cannot be found in this bundle, it falls back to the parent bundle (if
  it's not null) by calling the {@link #handleGetObject} method. If the resource still
  can't be found it throws a {@code MissingResourceException}.
  
  @param key
  the name of the resource.
  @return the resource object.
  @throws MissingResourceException
  if the resource is not found.