Day 13: Using Collectors.groupingBy and Collectors.counting to get numbers of file present of a particular type

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import java.io.IOException;
import java.nio.file.*;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

class Scratch {
    public static void main(String[] args) throws IOException, InterruptedException {
        Function<String, String> fileNameRemove = (fileName) -> {
            int index = fileName.lastIndexOf(".");
            if (index == -1) return "";
            return fileName.substring(index);
        };

        try (Stream<Path> paths = Files.walk(Paths.get("/home/mohibulhasan/Downloads"))) {
            Map<String, Long> fileCountByType = paths
                .filter(path -> Files.isRegularFile(path))
                .map(path -> path.getFileName().toString())
                .filter(fileName -> !fileName.isEmpty())
                .map(fileNameRemove)
                .collect(Collectors.groupingBy(
                    Function.identity(), Collectors.counting()
                ));
            System.out.println(fileCountByType);
        }
    }
}