code: public static String soyTemplateNameFromJavaClassName(String javaClass) {
      if (!javaClass.startsWith(CLASS_PREFIX)) {
        throw new IllegalArgumentException(
            "java class: " + javaClass + " is not a mangled soy template name");
      }
      return javaClass.substring(CLASS_PREFIX.length());
    }
docs: Translates a Java class name generated by {@link #javaClassNameFromSoyTemplateName}, back to
  the original soy template name.