Java 8枚举定义使用'new‘作为枚举值

public enum Day {
    MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}

public enum Day {
    MONDAY(new Date()), // 错误示例
    TUESDAY;

    private Date date;

    Day() {
        this.date = new Date();
    }

    Day(Date date) {
        this.date = date;
    }
}

public enum Day {
    MONDAY(new Date()),
    TUESDAY;

    private Date date;

    Day() {
        this.date = new Date();
    }

    Day(Date date) {
        this.date = date;
    }

    public Date getDate() {
        return date;
    }
}

public enum Day {
    MONDAY(new Date()),
    TUESDAY;

    private Date date;

    Day() {
        this.date = new Date();
    }

    Day(Date date) {
        this.date = date;
    }

    public Date getDate() {
        return date;
    }
}