I'm currently writing a program that needs to compare each file in an ArrayList of variable size. Right now, the way I'm doing this is through a nested code loop: if(tempList.size()>1){ for(int i=0;i<=tempList.size()-1;i++) //Nested loops. I should feel dirty? for(int j=i+1;j<=tempList.size()-1;j++){ //*Gets sorted. System.out.println(checkBytes(tempList.get(i), tempList.get(j))); } } I've read a few differing opinions on the necessity of nested loops, and I was wondering if anyone had a more efficient alternative. At a glance, each comparison is going to need to be done, either way, so the performance should be fairly steady, but I'm moderately convinced there's a cleaner way to do this. Any pointers?