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Java 8 - find first element in Stream that matches criteria

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Created by:

Brian-Tompset

491

In this article, we would like to show you how to find the first element in Stream that matches the criteria in Java 8.

In the example below, we use:

stream() - to create a stream from the List,
filter() - to specify the criteria (in our case if the element starts with "B"),
findFirst() - to return the first value that matches the criteria,
orElse() - to return null if none of the elements matches.

Practical example:

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import java.util.*;
​
public class Example {
​
    public static void main(String[] args) {
        // create list of strings
        List<String> letters = Arrays.asList("A1", "B1", "A2", "B2");
​
        // find first element that matches the criteria
        String result = letters.stream()
                .filter(x -> x.startsWith("B")) // <----- example criteria
                .findFirst()
                .orElse(null);
​
        System.out.println(result);  // B1
    }
}