Java 8 - Stream sorted (Comparator comparator) method in Java

Stream sorted(Comparator comparator) returns a stream consisting of the elements of this stream, sorted according to the provided Comparator

For ordered streams, the sort method is stable but for unordered streams, no stability is guaranteed. It is a stateful intermediate operation i.e, it may incorporate state from previously seen elements when processing new elements. 

In java 8, Comparator can be instantiated using lambda expression. We can also reverse the natural ordering as well as ordering provided by Comparator.

Syntax :

Stream<T> sorted(Comparator<? super T> comparator)

Where, Stream is an interface and T

is the type of stream elements.

comparator is used to compare stream elements.

Below given are some examples to understand the implementation of the function in a better way.

Example 1 :

// Implementation of Stream.sorted() 
// to get a stream of sorted elements 
// according to the provided Comparator 
import java.util.*; 
import java.util.stream.Stream; 
  
class javahubpoint { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // Creating a list of Integers 
        List<Integer> list = Arrays.asList(5, -10, 7, -18, 23); 
  
        System.out.println("The sorted stream according "
                           + "to provided Comparator is : "); 
  
        // Displaying the list of Strings in 
        // reverse order after sorting 
        list.stream().sorted(Comparator.reverseOrder()). 
                          forEach(System.out::println); 
    } 

Output :

The sorted stream according to provided Comparator is : 

23

7

5

-10

-18

Example 2 :

// Implementation of Stream.sorted() 
// to get a stream of sorted elements 
// according to the provided Comparator 
import java.util.*; 
import java.util.stream.Stream; 
  
class javahubpoint { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // Creating a list of Strings 
        List<String> list = Arrays.asList("javahubpoint", "for", 
                    "javahubpointfor", "javahubpointQuiz", "javahubpoint"); 
  
        System.out.println("The sorted stream according "
                           + "to provided Comparator is : "); 
  
        // Displaying the list of Strings in 
        // reverse order after sorting 
        list.stream().sorted(Comparator.reverseOrder()). 
                            forEach(System.out::println); 
    } 

Output :

The sorted stream according to provided Comparator is : 

for

javahubpointfor

javahubpointQuiz

javahubpoint

javahubpoint

Example 3 :



// Implementation of Stream.sorted() 
// to get a stream of sorted elements 
import java.util.*; 
import java.util.stream.Stream; 
  
class javahubpoint { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // Creating an array of Strings 
        String[] array = { "javahubpoint", "javahubpoint", "for", 
                           "javahubpointfor", "javahubpointQuiz" }; 
  
        System.out.println("The sorted stream is :"); 
  
        // sorting the elements of array based 
        // on their last character 
        Stream.of(array).sorted((str1, str2) 
                     -> Character.compare(str1 
                     .charAt(str1.length() - 1), 
                    str2.charAt(str2.length() - 1))) 
            .         forEach(System.out::println); 
    } 

Output :

The sorted stream is :

javahubpoint

for

javahubpoint

javahubpointfor

javahubpointQuiz