Java Stream findAny() with examples

Stream findAny() returns an Optional (a container object which may or may not contain a non-null value) describing some element of the stream, or an empty Optional if the stream is empty.

findAny() V/s findFirst() :

The findAny() method returns any element from a Stream but there might be a case where we require the first element of a filtered stream to be fetched. When the stream being worked on has a defined encounter order(the order in which the elements of a stream are processed), then findFirst() is useful which returns the first element in a Stream.

Syntax :

Optional<T> findAny()

Where, Optional is a container object which
may or may not contain a non-null value 
and T is the type of objects and the function
returns an Optional describing some element of
this stream, or an empty Optional if the stream is empty.

Exception : If the element selected is null, NullPointerException is thrown.

Note : findAny() is a terminal-short-circuiting operation of Stream interface. This method returns any first element satisfying the intermediate operations. This is a short-circuit operation because it just needs ‘any’ first element to be returned and terminate the rest of the iteration.

Example 1 : findAny() method on Integer Stream.

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// Java code for Stream findAny()
// which returns an Optional describing
// some element of the stream, or an
// empty Optional if the stream is empty.
import java.util.*;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
  
        // Creating a List of Integers
        List<Integer> list = Arrays.asList(2, 4, 6, 8, 10);
  
        // Using Stream findAny() to return
        // an Optional describing some element
        // of the stream
        Optional<Integer> answer = list.stream().findAny();
  
        // if the stream is empty, an empty
        // Optional is returned.
        if (answer.isPresent()) {
            System.out.println(answer.get());
        }
        else {
            System.out.println("no value");
        }
    }
}

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Output :


2



Example 2 : findAny() function on Stream of Strings. 











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// Java code for Stream findAny() 


// which returns an Optional describing 


// some element of the stream, or an 


// empty Optional if the stream is empty. 


import java.util.*; 


  


class GFG { 


  


    // Driver code 


    public static void main(String[] args) 


    { 


  


        // Creating a List of Strings 


        List<String> list = Arrays.asList("Geeks", "for", 


                                          "GeeksQuiz", "GFG"); 


  


        // Using Stream findAny() to return 


        // an Optional describing some element 


        // of the stream 


        Optional<String> answer = list.stream().findAny(); 


  


        // if the stream is empty, an empty 


        // Optional is returned. 


        if (answer.isPresent()) { 


            System.out.println(answer.get()); 


        } 


        else { 


            System.out.println("no value"); 


        } 


    } 


} 



















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Output :


Geeks



Note : The behavior of Stream findAny() operation is explicitly non-deterministic i.e, it is free to select any element in the stream. Multiple invocations on the same source may not return the same result.

Example 3 : findAny() method to return the elements divisible by 4, in a non-deterministic way.











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// Java code for Stream findAny()  


// which returns an Optional describing 


// some element of the stream, or an  


// empty Optional if the stream is empty. 


import java.util.OptionalInt; 


import java.util.stream.IntStream; 


  


class GFG { 


      


    // Driver code 


    public static void main(String[] args) { 


          


    // Creating an IntStream 


    IntStream stream = IntStream.of(4, 5, 8, 10, 12, 16) 


                       .parallel(); 


      


    // Using Stream findAny().  


    // Executing the source code multiple times 


    // may not return the same result. 


    // Every time you may get a different  


    // Integer which is divisible by 4. 


    stream = stream.filter(i -> i % 4 == 0); 


  


    OptionalInt answer = stream.findAny(); 


    if (answer.isPresent())  


    { 


        System.out.println(answer.getAsInt()); 


    } 


} 


} 



















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Output :


16




          
          
          
          

            

    

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