TYou might try this as it does the same thing.

1. IBI_INTERVAL_SORT_asc {
2.     public int compare(IBI_Sample ibi1, IBI_Sample ibi2) {
3.         return new Float(ibi1.interval).compareTo(new Float(ibi2.interval));
   
4.     }
5. }

to reverse the sort order swap the ibi1 and ibi2 in line 3

thanks, i will try it asap

Making two new objects on each comparison is quite costly, as it will generate lot of garbage and will make more frequent pauses (when garbage collector will run).
Nothing wrong with the code above (as long as you don't have to deal with NaN and such), I will just remove the else.

you mean that the last line will be

i agree on that :)