List files in a Stream recursively (depth-first)

StreamFiles.java

import java.io.File;
import java.util.Arrays;
import java.util.stream.Stream;

public class StreamFiles {
    public static Stream<File> recursive(File file) {
        File[] listed = file.listFiles();
        if (listed == null) {
            return Stream.of(file);
        }
        return Stream.concat(
                Stream.of(file),
                Arrays.stream(listed).flatMap(StreamFiles::recursive));
    }
}