You can use
Collections.sort(yourArrayList);But there is some work you need to do. You have to implement Comparable interface in your class. There will be a method called compareTo (Object o) which you need to override. Here you are free to code how you should sort (using first name or last name or title), such that it should return an integer. Your sort will depend on whether you return a -ve, +ve or zero integer.
Any other clarification required, just post.