程序: class MyDate{ private int year; private int month; private int day; public MyDate( int year, int month,int day){ this.year=year; this.month=month; this.day=day; } //Override Method } 为了让new MyDate(1980,11,9)==(判断是否相等)new MyDate(1980,11,9) 返 回true,必须在Override Method处覆盖哪个方法?()