ArrayList, Set Sorting in Ascending –
Descending Order Java
Sorting
List, Set and ArrayList in Java on ascending and descending order is very easy,
You just need to know correct API method to do that. Collections.sort() method will sort the collection passed to it,
doesn't return anything just sort the collection itself. Sort() method of Collections class in Java is overloaded where
another version takes a Comparator and sort all the elements of Collection on
order defined by Comparator.If we don't pass any Comparator than object will be sorted based upon there natural order
like String will be sorted alphabetically or lexicographically. Integer will be
sorted numerically etc. Default sorting order for an object is ascending order
like Integer will be sorted from low to
high while descending order is just opposite. Collections.reverseOrder() returns a Comparator which will be
used for sorting Object in descending order.
Sorting List in ascending and descending order - Example

package example;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
/**
* Java program Example of sorting List, ArrayList and Set on ascending and descending order
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
/**
* Java program Example of sorting List, ArrayList and Set on ascending and descending order
* in Java.
* Collections.sort() method is used for sorting collection and Collections.reverseOrder()
* will sort elements of Collections in descending order.
* @author Javin Paul
*/
public class CollectionSortingExample{
public static void main(String args[]) throws InterruptedException{
// Sort List and Set in ascending order
// Sorting List in Java in ascending order in Java
List<Integer> list = Arrays.asList( 1, 2, 5, 9, 3, 6, 4, 7, 8);
System.out.println("Unsorted List in Java: " + list);
// Sorting List into Java now, Collections.sort() method will sort
* Collections.sort() method is used for sorting collection and Collections.reverseOrder()
* will sort elements of Collections in descending order.
* @author Javin Paul
*/
public class CollectionSortingExample{
public static void main(String args[]) throws InterruptedException{
// Sort List and Set in ascending order
// Sorting List in Java in ascending order in Java
List<Integer> list = Arrays.asList( 1, 2, 5, 9, 3, 6, 4, 7, 8);
System.out.println("Unsorted List in Java: " + list);
// Sorting List into Java now, Collections.sort() method will sort
// the collection passed
// to it. Doesn't return anything it just sort the collection itself
Collections.sort(list); //sorting collection
System.out.println("List in Java sorted in ascending order: " + list);
// sorting List in descending order in Java, Collections.sort() method can be used
// to sort all element in descending order if we pass it comparator which can
// return descending order for elements. here is an example of sorting List
// in descending order in Java
// Collection class provides a in built-in comparator for that which can
// sort objects in reverse order i..e descending order for Integers or
// any other Object in Java
Collections.sort(list, Collections.reverseOrder());
System.out.println("Java List sorted in descending order: " + list);
// Any List implementation in Java like ArrayList, LinkedList
// can be sorted in ascending and descending order in Java by following above
// example, let's see a quick example for sorting ArrayList and LinkedList
// in ascending and descending order in Java
//Sorting ArrayList in ascending order in Java
ArrayList alphabets = new ArrayList();
alphabets.add("c");
alphabets.add("b");
alphabets.add("a");
alphabets.add("d");
System.out.println("Unsorted ArrayList in Java : " + alphabets);
//Sorting ArrayList into ascending order
Collections.sort(alphabets);
System.out.println("Sorted ArrayList in ascending order in Java : " + alphabets);
//Sorting ArrayList into descending order or reverse order in Java
Collections.sort(alphabets, Collections.reverseOrder());
System.out.println("ArrayList sort in descending order in Java : " + alphabets);
}
}
Output:
Unsorted List in Java: [1, 2, 5, 9, 3, 6, 4, 7, 8]
List in Java sorted in ascending order: [1, 2, 3, 4, 5, 6, 7, 8, 9]
Java List sorted in descending order: [9, 8, 7, 6, 5, 4, 3, 2, 1]
Unsorted ArrayList in Java : [c, b, a, d]
Sorted ArrayList in ascending order in Java : [a, b, c, d]
ArrayList sort in descending order in Java : [d, c, b, a]
// to it. Doesn't return anything it just sort the collection itself
Collections.sort(list); //sorting collection
System.out.println("List in Java sorted in ascending order: " + list);
// sorting List in descending order in Java, Collections.sort() method can be used
// to sort all element in descending order if we pass it comparator which can
// return descending order for elements. here is an example of sorting List
// in descending order in Java
// Collection class provides a in built-in comparator for that which can
// sort objects in reverse order i..e descending order for Integers or
// any other Object in Java
Collections.sort(list, Collections.reverseOrder());
System.out.println("Java List sorted in descending order: " + list);
// Any List implementation in Java like ArrayList, LinkedList
// can be sorted in ascending and descending order in Java by following above
// example, let's see a quick example for sorting ArrayList and LinkedList
// in ascending and descending order in Java
//Sorting ArrayList in ascending order in Java
ArrayList alphabets = new ArrayList();
alphabets.add("c");
alphabets.add("b");
alphabets.add("a");
alphabets.add("d");
System.out.println("Unsorted ArrayList in Java : " + alphabets);
//Sorting ArrayList into ascending order
Collections.sort(alphabets);
System.out.println("Sorted ArrayList in ascending order in Java : " + alphabets);
//Sorting ArrayList into descending order or reverse order in Java
Collections.sort(alphabets, Collections.reverseOrder());
System.out.println("ArrayList sort in descending order in Java : " + alphabets);
}
}
Output:
Unsorted List in Java: [1, 2, 5, 9, 3, 6, 4, 7, 8]
List in Java sorted in ascending order: [1, 2, 3, 4, 5, 6, 7, 8, 9]
Java List sorted in descending order: [9, 8, 7, 6, 5, 4, 3, 2, 1]
Unsorted ArrayList in Java : [c, b, a, d]
Sorted ArrayList in ascending order in Java : [a, b, c, d]
ArrayList sort in descending order in Java : [d, c, b, a]
As shown in this sort example of ArrayList and Set, You can sort LinkedList on ascending and descending order in Java. Since Collections.sort() method is applicable to Collection
interface, any Collection implementation like Set, HashSet can also be sorted
in ascending, descending or reverse order of elements. Sorting Array in Java is
completely different than sorting collection in Java which we will see in next
tutorial. Now you learned how to sort Collection in Java including frequently used collection like ArrayList, List , Set and HashSet.
Further Learning
Java In-Depth: Become a Complete Java Engineer
Java Fundamentals: Collections
Data Structures and Algorithms: Deep Dive Using Java
What is difference between ArrayList and Vector in Java
How to iterate over ArrayList in Java
How to loop Map in Java with Example
Difference between ConcurrentHashMap and Hashtable in Java
Difference between Hashtable and HashMap in Java
Further Learning
Java In-Depth: Become a Complete Java Engineer
Java Fundamentals: Collections
Data Structures and Algorithms: Deep Dive Using Java
What is difference between ArrayList and Vector in Java
How to iterate over ArrayList in Java
How to loop Map in Java with Example
Difference between ConcurrentHashMap and Hashtable in Java
Difference between Hashtable and HashMap in Java
Hi, I don't see any set there for sorting.
ReplyDeleteYes u r right No changes done..
DeleteHi, can you elaborate?
Delete