Ordering & Sorting are 2 distinct names to same concept .
Java has the concept of Natural Ordering means objects like Strings are self ordered in java .
Hence collections that contain
string as key or string as objects are by default sorted .
Collections like List,Set ,Map need sorting . There are variants to these also like SortedSet , TreeSet etc .
ArrayList,HashMap,Hashtables need sorting...
If you want your objects to be sorted you have to implement a Comparator interface for that . It has a method compareTo(Object 1 , Object2) that sorts 2 objects while adding them in Collections.
There is also a utility method sort(Collection collection) on Collections class that sorts the collection .