How to Sort an ArrayList in Java?

Use `Collections.sort(list);` for natural ordering

Use `list.sort(Comparator.naturalOrder());` for natural ordering

Use `list.sort(Comparator.reverseOrder());` for reverse ordering

Use `Collections.sort(list, comparator);` for custom sorting

Use `list.sort((a, b) -> a.compareTo(b));` for custom comparison

Use `list.sort(Comparator.comparing(MyClass::getField));` for sorting by a field

Use `list.sort(Comparator.comparing(MyClass::getField).reversed());` for reverse field sorting

Use `Collections.sort(list, (a, b) -> Integer.compare(a.getAge(), b.getAge()));` for lambda-based sorting

Use `list.sort(null);` to sort using natural order

Ensure the elements implement `Comparable` for natural sorting