import java.text.*;
public class Time
{
    int hours;
    int minutes;
    int seconds;
    
    Time()
    {
        hours=00;
        minutes=00;
        seconds=00;
        System.out.println("From the default constructor:"
        +"\n Createed a new Time object with data values"
        +"\n hours="+hours  + "minutes="+minutes  + "seconds="+seconds);
    }    
    Time(long hhmmss)      //第二个构造方法
    {
        hours = (int)(hhmmss/10000.0);              //抽时
        minutes = (int)((hhmmss-hh*10000.0)/100.0);
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        seconds = (int)(hhmmss-hh*10000-mm*100.0);
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        System.out.println("From the default constructor:"
        +"\n Createed a new Time object with data values"
        +"\n hours="+hours  + "minutes="+minutes  + "seconds="+seconds);
    }
    public void setTime(int hh,int mm,int ss)
    {
        hours=hh;
        minutes=mm;
        seconds=ss;
    }
    public void showTime()
    {
        DecimalFormat df =new DecimalFormat("0");
        System.out.println("The Time is"+df.format(hours%100)+ '/'+df.format(minutes)+'/'+df.format(seconds));
                               //精确到最后两位
    }
    public static void main(String[] args)
    {
        Time a=new Time();       //声明一个Time类型的对象
        Time b=new Time(111930);
    
    }
}

你在第二个构造方法利用的 hh  mm貌似不是类的成员，你在这个构造方法里好像也没有定义。

minutes = (int)((hhmmss-hours*10000.0)/100.0);
                                          ~~~~~
        seconds = (int)(hhmmss-hours*10000-minutes*100.0);
                                         ~~~~~       ~~~~~~~

60172336(java学习群，欢迎各位加入）