Example of Files.list() resource leaks for Spot Bugs

FilesListExample.java

package com.jamesdaily.spotbugs.FileDescriptorLeak;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;

public class FilesListExample {

	/*
	 * SpotBugs should detect and warn about the unclosed input stream created
	 * by Files.list().
	 * 
	 * https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#list-java.nio.file.Path-
	 * 
	 * "The returned stream encapsulates a DirectoryStream. If timely disposal
	 * of file system resources is required, the try-with-resources construct
	 * should be used to ensure that the stream's close method is invoked after
	 * the stream operations are completed."
	 * 
	 */

	public static void main(String[] args) {

		final String dir = "./";

		System.out.println("Starting processFilesFluidForEach()...");
		processFilesFluidForEach(dir);

		System.out.println("Starting processFilesExplicitStream()...");
		processFilesExplicitStream(dir);

		System.out.println("Starting processFilesExplicitStreamTryWithResources()...");
		processFilesExplicitStreamTryWithResources(dir);
	}

	/**
	 * Compiler/IDE helpfully warns: "Resource leak: 'files' is never closed"
	 */
	private static void processFilesExplicitStream(String pathdir) {

		Path path = Paths.get(pathdir);

		try {
			Stream<Path> files = Files.list(path);
			files.forEach(System.out::println);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * Compiler/IDE fails to warn. 
	 * Files.list(path) Stream is never closed
	 * (.forEach() does not close it)
	 */
	private static void processFilesFluidForEach(String pathdir) {
		Path path = Paths.get(pathdir);

		try {
			Files.list(path).forEach(System.out::println);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * No warning needed, since Stream is auto-closed via try-with-resources
	 */
	private static void processFilesExplicitStreamTryWithResources(String pathdir) {

		Path path = Paths.get(pathdir);

		try (Stream<Path> files = Files.list(path)) {
			files.forEach(System.out::println);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}