Lists of Custom Types and Sorting

To sort such a list, your Apex class can implement the Comparator interface and pass it as a parameter to the List.sort method. Alternatively, your Apex class can implement the Comparable interface.

The sort criteria and sort order depend on the implementation that you provide for the Comparable.compareTo or the Comparator.compare method.

To perform locale-sensitive comparisons and sorting, use the Collator class. Because locale-sensitive sorting can produce different results depending on the user running the code, avoid using it in triggers or in code that expects a particular sort order.