*     Java 8 and removed in Java 9. We do not plan to remove this API from Guava, but if you are
   *     using it, it is probably not doing what you want.
   */
  @Deprecated
  JAVA_EXT_DIRS("java.ext.dirs"),

  /** Operating system name. */
  OS_NAME("os.name"),

  /** Operating system architecture. */
  OS_ARCH("os.arch"),

  /** Operating system version. */
  OS_VERSION("os.version"),