Java File Class

// In this Java program, we accepts a file or directory name
// from command line arguments. Then the program will check
// if that file or directory physically exist or not and it
// displays the property of that file or directory.

import java.io.File;

// Displaying file property
class CheckFileExist 
{
    public static void main(String[] args)
    {

        // Accept file name or directory name through
        // command line args
        String fname = args[0];

        // pass the filename or directory name to File
        // object
        File f = new File(fname);

        // apply File class methods on File object
        System.out.println("File name :" + f.getName());
        System.out.println("Path: " + f.getPath());
        System.out.println("Absolute path:" + f.getAbsolutePath());
        System.out.println("Parent:" + f.getParent());
        System.out.println("Exists :" + f.exists());

        if (f.exists()) {
            System.out.println("Is writable:" + f.canWrite());
            System.out.println("Is readable" + f.canRead());
            System.out.println("Is a directory:" + f.isDirectory());
            System.out.println("File Size in bytes " + f.length());
        }
    }
}

// Java Program to display all
// the contents of a directory
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;

// Displaying the contents of a directory
class AllDir 
{
    public static void main(String[] args)
        throws IOException
    {
        // Enter the path and dirname
        BufferedReader br = new BufferedReader(
            new InputStreamReader(System.in));

        System.out.print("Enter directory path : ");
        String dirpath = br.readLine();
      
        System.out.print("Enter the directory name : ");
        String dname = br.readLine();

        // Create File object with dirpath and dname
        File f = new File(dirpath, dname);

        // If directory exists,then
        if (f.exists()) {
            
          	// Get the contents into arr[]
            // now arr[i] represent either a File or
            // Directory
            String arr[] = f.list();

            // Find no. of entries in the directory
            int n = arr.length;

            // Displaying the entries
            for (int i = 0; i < n; i++) {

                System.out.print(arr[i] + " ");

                // Create File object with the entry and
                // test if it is a file or directory
                File f1 = new File(f,arr[i]);

                if (f1.isFile())
                    System.out.println(": is a file");
                if (f1.isDirectory())
                    System.out.println(": is a directory");
            }

            System.out.println("\nNo of entries in this directory : " + n);
        }
        else
            System.out.println("Directory not found");
    }
}