public static PluginSpec readPluginSpecFile(URL pluginSpec) throws IOException {
        return (PluginSpec) mapper.reader(PluginSpec.class).readValue(pluginSpec);
    }
Reads a plugin spec file and returns a {@link PluginSpec}.
@param pluginSpec the plugin spec
@throws IOException when an unhandled exception occurs
@return plugin's specification
common/plugin/src/main/java/io/apiman/common/plugin/PluginUtils.java