LINE_SEPARATOR("line.separator"),

  /** User's account name. */
  USER_NAME("user.name"),

  /** User's home directory. */
  USER_HOME("user.home"),

  /** User's current working directory. */
  USER_DIR("user.dir");

  private final String key;

  StandardSystemProperty(String key) {
    this.key = key;
  }

  /** Returns the key used to look up this system property. */
  public String key() {

        System.out.println(SystemUtil.PATH_SEPARATOR);
        System.out.println(SystemUtil.OS_NAME);
        System.out.println(SystemUtil.JAVA_IO_TMPDIR);
        System.out.println(SystemUtil.USER_DIR);
        System.out.println(SystemUtil.USER_HOME);
    }