How to Recursively List All Files in a Directory Using Java?

What is the method to recursively list all files under a directory in Java, and does the Java framework provide a utility for this?

// Java code to recursively list files using Files.walk method
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 ListFiles {
    public static void main(String[] args) {
        String directoryPath = "path/to/directory";
        try (Stream<Path> paths = Files.walk(Paths.get(directoryPath))) {
            paths.filter(Files::isRegularFile)
                 .forEach(System.out::println);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Recursively listing files in a directory in Java can be efficiently done using the NIO (New I/O) package, which provides a more versatile way for file operations compared to traditional IO.

// Using Files.walk to list files in a directory
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 ListFiles {
    public static void main(String[] args) {
        String directoryPath = "path/to/directory";
        try (Stream<Path> paths = Files.walk(Paths.get(directoryPath))) {
            paths.filter(Files::isRegularFile)
                 .forEach(System.out::println);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Causes

• Unstructured or inefficient file listing implementations.
• Limited knowledge of Java NIO framework.
• Use of outdated file handling techniques.

Solutions

• Use the `Files.walk` method from the `java.nio.file` package for a streamlined approach.
• Apply filters to list only specific file types if necessary.
• Utilize exception handling to manage errors during file access.

Mistake: Not handling IOException when accessing files.

Solution: Always wrap file access code in try-catch blocks to handle possible exceptions.

Mistake: Ignoring symbolic links which could lead to infinite loops.

Solution: Use filters to prevent following symbolic links using `Files.isRegularFile()`.