Parameter
|
Comparable
|
Comparator
|
| Sorting logic | Sorting logic must be in same class whose objects are being sorted. Hence this is called natural ordering of objects | Sorting logic is in separate class. Hence we can write different sorting based on different attributes of objects to be sorted. E.g. Sorting using id,name etc. |
| Implementation | Class whose objects to be sorted must implement this interface.e.g Country class needs to implement comparable to collection of country object by id | Class whose objects to be sorted do not need to implement this interface.Some other class can implement this interface. E.g.-CountrySortByIdComparator class can implement Comparator interface to sort collection of country object by id |
Sorting method | int compareTo(Object o1)
This method compares this object with o1 object and returns a integer.Its value has following meaning
1. positive – this object is greater than o1
2. zero – this object equals to o1
3. negative – this object is less than o1 | int compare(Object o1,Object o2)
This method compares o1 and o2 objects. and returns a integer.Its value has following meaning.
1. positive – o1 is greater than o2
2. zero – o1 equals to o2
3. negative – o1 is less than o1 |
| Calling method | Collections.sort(List)
Here objects will be sorted on the basis of CompareTo method | Collections.sort(List, Comparator)
Here objects will be sorted on the basis of Compare method in Comparator |
| Package |
Java.lang.Comparable
| Java.util.Comparator |
