code: public final T fromJson(Reader in) throws IOException {
      JsonReader reader = new JsonReader(in);
      return read(reader);
    }
docs: Converts the JSON document in {@code in} to a Java object. Unlike Gson's
  similar {@link Gson#fromJson(java.io.Reader, Class) fromJson} method, this
  read is strict. Create a {@link JsonReader#setLenient(boolean) lenient}
  {@code JsonReader} and call {@link #read(JsonReader)} for lenient reading.
  
  @return the converted Java object. May be null.
  @since 2.2