RetroSearch Browse

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://www.geeksforgeeks.org/java/stream-findfirst-java-examples/ below:

Stream findFirst() in Java with examples

Last Updated : 06 Dec, 2018

Stream findFirst()

returns an Optional (a container object which may or may not contain a non-null value) describing the

first

element of this stream, or an empty Optional if the stream is empty. If the stream has no encounter order, then any element may be returned.

Syntax :

Optional<T> findFirst()

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 the first 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 first element satisfying the intermediate operations.

Example 1 :

findFirst() function on Stream of Integers.

Java


 // Java code for Stream findFirst()
// which returns an Optional describing
// the first element of this 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(3, 5, 7, 9, 11);

        // Using Stream findFirst()
        Optional<Integer> answer = list.stream().findFirst();

        // if the stream is empty, an empty
        // Optional is returned.
        if (answer.isPresent()) {
            System.out.println(answer.get());
        }
        else {
            System.out.println("no value");
        }
    }
}

Output :

Example 2 :

findFirst() function on Stream of Strings.

Java


 // Java code for Stream findFirst()
// which returns an Optional describing
// the first element of this 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("GeeksforGeeks", "for",
                                          "GeeksQuiz", "GFG");

        // Using Stream findFirst()
        Optional<String> answer = list.stream().findFirst();

        // if the stream is empty, an empty
        // Optional is returned.
        if (answer.isPresent()) {
            System.out.println(answer.get());
        }
        else {
            System.out.println("no value");
        }
    }
}

Output :

GeeksforGeeks

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4