code: public InputSource resolveEntity(String publicId, String systemId) {
          if (systemId != null && systemId.startsWith("file:")) {
              return null;
          } else {
              return new InputSource();
          }
      }
docs: Resolve the entity if it's referring to a local schema. Otherwise, return
  an empty InputSource. This behavior is required in order to ensure that
  Xerces never attempts to load external schemas specified with
  xsi:schemaLocation. It is not enough that we specify
  processContents="skip" in our own schema.