How to Delete a Directory in Java

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In this post, we will see how you can delete directories in Java using both traditional and modern techniques. 

1. The Traditional Way: Using java.io.File 

The java.io.File class has been part of Java for a long time. It offers simple methods to work with files and directories. 

1.1. Deleting an Empty Directory

import java.io.File;

public class DirectoryDeletionDemo {
    public static void main(String[] args) {
        File dir = new File("myEmptyDirectory");

        if(dir.delete()) {
            System.out.println("Empty directory deleted successfully");
        } else {
            System.out.println("Failed to delete the directory.");
        }
    }
}
This approach works fine for empty directories, but what if the directory contains files or other subdirectories?

1.2. Deleting a Directory Recursively 

To delete a directory that contains files or other subdirectories, you need a recursive approach.
public class RecursiveDeletionDemo {

    public static void main(String[] args) {
        File dir = new File("myDirectory");
        deleteDirectory(dir);
    }

    public static boolean deleteDirectory(File dir) {
        if (dir.isDirectory()) {
            for (File child : dir.listFiles()) {
                deleteDirectory(child);
            }
        }
        return dir.delete();
    }
}

2. The Modern Way: Using java.nio.file.Files 

2.1 Delete Empty Directory

For empty directories, the Files.delete() method can be directly used.
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.io.IOException;

public class DeleteDirectory {

    public static void main(String[] args) {
        Path dirPath = Paths.get("myEmptyDirectory");

        try {
            Files.delete(dirPath);
            System.out.println("Directory deleted successfully!");
        } catch (IOException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

2.2. Deleting Directories using Files.walkFileTree()

The Files class in the NIO.2 API provides a walkFileTree method, which can be used to traverse and delete directories recursively.

import java.nio.file.FileVisitOption;
import java.nio.file.FileVisitResult;
import java.nio.file.FileVisitor;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.io.IOException;
import java.util.EnumSet;

public class NIODirectoryDeletionDemo {

    public static void main(String[] args) {
        Path rootPath = Paths.get("myDirectory");
        try {
            Files.walkFileTree(rootPath, EnumSet.noneOf(FileVisitOption.class), Integer.MAX_VALUE, new SimpleFileVisitor<Path>() {
                @Override
                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                    Files.delete(file);
                    return FileVisitResult.CONTINUE;
                }

                @Override
                public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
                    Files.delete(dir);
                    return FileVisitResult.CONTINUE;
                }
            });
            System.out.println("Directory deleted successfully using NIO.2");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Conclusion

While the java.io.File class provides straightforward methods for directory deletion, the java.nio.file.Files class in the NIO.2 API offers a more robust and efficient solution, especially for recursive deletion. Depending on your application's requirements and the Java version you are using, you can opt for the method that suits you best. Always remember to back up essential data before performing deletion operations, as they are irreversible.

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