Java 8 Streams - Stream.count Examples

[Last Updated: Nov 8, 2025]

Interface:

java.util.stream.Stream

Method:

long count()

This method returns the count of elements in this stream. This is a special case of a reduction and is equivalent to:

mapToLong(e > 1L).sum()

This is a terminal operation.

Examples

Using Stream#count method and comparing with equivalent reduce operation.

package com.logicbig.example;

import java.util.stream.Stream;

public class CountExample {
    public static void main (String[] args) {
        runCount();
        runEquivalentReduce();
        runEquivalentSum();
    }

    private static void runCount () {
        long c = Stream.of("banana", "pie", "apple").count();
        System.out.println(c);
    }

    private static void runEquivalentReduce () {
        long sum = Stream.of("banana", "pie", "apple")
                         .mapToLong(s -> 1L)
                         .reduce(0, Long::sum);
        System.out.println(sum);
    }

    private static void runEquivalentSum () {
        long sum = Stream.of("banana", "pie", "apple")
                         .mapToLong(s -> 1L).sum();
        System.out.println(sum);
    }
}

Output

3
3
3

Original Post

Java 8 Streams - Stream.count Examples

Interface:

Method:

Examples

Output

See Also