Question

How do I correct this error in my code?

When it got to the file type I can only go "null" from a certain point and I'm wondering how to correct this error.
Also can I get a word document on this coding strategy for this problem? How much of this am I doing correctly?

The original problem description:

Create a program that provides a listing of all the files in a directory. The program should be a Java application that accepts a single argument into the args array of the main() method. This argument identifies the name of a directory. The application should make sure that this filename really does identify a directory and then list all of the files in the directory. For each file, list whether the file is a file or a directory and list the size for each file. The program should print its output to System.out.

Task List X fileproject - FileProject/src/FileProject.java - Eclipse IDE HOLA COME BEI Package Explorer X FileProject.java X package-info.java i import java.io.File; FileProject 30 /** EJRE System Library [JavaSE-11] src 7 /** (default package) 8 * @author sauceuke FileProject.java 10 */ fileproject 11 public class FileProject { ► package-info.java Find All Activ... * @param args O Connect Mylyn Connect to your task and ALM or create a local task. 160 public static void main(String[] args) { 17 File folderName = new File("abcd"); 18 File[] files = folderName. listFiles(); 19 String filetype = ""; 20 System.out.println("Name \t\t file/directory It file size(if it is file 21 for (File file: files) 22 { if(file.isDirectory()) { filetype = "Directory''; Outlinex 24 File Project main(String[]) : void File file = null; if(file.isFile()) { filetype = "File"; System.out.println(file.getName() + "t\t"+ filetype +"\t\t"+ file.length Problems Javadoc Declaration Console X Coverage XX Bal B PA- <terminated FileProject (Java Application) /Library/Java/JavaVirtual Machines/jdk-11.0.2.jdk/Contents/Home/bin/java (Mar 9, 2020, 5:21:52 PM Name file/directory file size( if it is file) Exception in thread "main" java.lang.NullPointerException at FileProject.main FileProject.java:21 306M of 368M U

• Embed the program in a Microsoft Word document with a description of your programming strategy.

Answer 1

FIXED JAVA CODE:

import java.io.File;

public class Main {

    public static void main(String[] args) {

        File folderName = new File(args[0]);// get directory name from command line arguments

        // check if folderName is really a directory or not

        if (!folderName.isDirectory()) {

            System.out.println(args[0] + " is not a directory");

            System.exit(1);// quit the program

        }

        File[] files = folderName.listFiles();

        String filetype = "";

        System.out.println("Name \t\t file/directory \t file size (if it is file)");

        // Loop through all files in the folder

        for (File file : files) {

            // If it is a directory

            if (file.isDirectory()) {

                filetype = "directory";

                System.out.println(file.getName() + "\t\t" + filetype);

            }

            // If it is a file

            if (file.isFile()) {

                filetype = "file";

                System.out.println(file.getName() + "\t\t" + filetype + "\t\t" + file.length());

            }

        }

    }

}

SAMPLE OUTPUT:

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