The Collectors.counting retuns a Collector that counts the number of elements in the stream.
Java 8 Stream Collectors.counting() exmaple
The example counts the number of elements in the list:
import java.util.List; import java.util.ArrayList; import java.util.stream.Collectors; public class JavaCollectToListEx { public static void main(String[] args) { List < String > programmingLanguages = new ArrayList < > (); programmingLanguages.add("C"); programmingLanguages.add("C++"); programmingLanguages.add("Java"); programmingLanguages.add("Kotlin"); programmingLanguages.add("Python"); programmingLanguages.add("Perl"); programmingLanguages.add("Ruby"); // filter all four character words into a list long result = programmingLanguages.stream().collect(Collectors.counting()); System.out.println(result); } }
Output:
7
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