Majik Coding Speedcode Episode #1 - Simple Java Timer with Countdown

In this video I made a timer in Java that also has a countdown. I am very new to coding and so any help would be appreciated!

Also, I messed up again, the code at the bottom of interface should be:

public double setHour(double thetime) {
hour = thetime/3600000;
return hour;
}
public double setrMin(double thetime) {
rmin = thetime%3600000/60000;
return rmin;
}
public double setrSec(double thetime) {
rsec = thetime%3600000%60000/1000;
return rsec;
}

Music Used -
Your Lie In April Best OST Covers -