private class myComparator implements Comparator<Interval> {
@Override
public int compare(Interval a, Interval b) {//things to compare
//comparissons here.
//1. if we want a to evaluate to left(go before) we return -1
//2. if we want a to evaluate to right(go after) we return 1
//3 .if we need to reevaluate for more ocnditions we return 0
// and reevaluate steps 1 & 2 until we can return 1 or -1
return a.start < b.start ? -1 : a.start == b.start ? 0 : 1;
}
}
//usage:
Collections.sort(intervals, new myComparator());