public static int hashCode(final IJsonConfigurable<?> jsonConfig) {
        if (jsonConfig == null) {
            return 7;
        }
        final JsonNode node = jsonConfig.getJsonConfig();
        return node == null ? 13 : node.hashCode();
    }
Helper method to implement HashCode for an object implementing IJsonConfiguration
main/src/main/java/cgeo/geocaching/utils/config/JsonConfigurationUtils.java