Question

In Java, please create a new Java application called "CheckString" (without the quotation marks) according to the following guidelines.

** Each method below, including main, should handle (catch) any Exceptions that are thrown. ** ** If an Exception is thrown and caught, print the Exception's message to the command line. **

1. Write a complete Java method called checkWord that takes a String parameter called word, returns nothing, and is declared to throw an Exception of type Exception. In the method, check if the first character of the parameter is a letter. If it is not a letter, the method throws an Exception of type Exception with the message of: "This is not a word."
2. Write a complete Java method called getWord that takes no parameters and returns a String. The method prompts the user for a word, and then calls the checkWord method you wrote in #1 above, passing as a parameter the word the user provided as input. Make sure the getWord method handles the Exception that may be thrown by checkWord.
3. Write a complete Java method called writeFile that takes two parameters: an array of Strings (arrayToWrite) and a String (filename). The method writes the Strings in the arrayToWrite array to a text file called filename (the parameter), with each String on a separate line.
4. Write a complete Java method called readFile that takes a String as a parameter (filename) and returns an ArrayList of Strings (fileContents). The method reads the text file identified by the filename parameter and populates the ArrayList with an element for each line in the text file.
5. In your main method, do the following in the order specified:
   1. Call the getWord method you wrote in #2 above and print the result to the command line.
   2. Create an array of Strings called testData and populate it with at least three elements.
   3. Call the writeFile method you wrote in #3 above passing the array you created in #5.2 and the String "data.txt".
   4. Call the readFile method you wrote in #4 above to read the file you wrote in #5.3. Assign the result of readFile to an ArrayList variable in main called fileContents.
   5. Write a loop to print the contents of the fileContents ArrayList to the command line.

Answer 1

thanks for the question, here are the all methods written in Java.

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import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;

public class CheckString {

    public static void checkWord(String word) throws Exception {

        if (word == null || !Character.isLetter(word.charAt(0))) {
            throw new Exception("This is not a word");
        }
    }

    public static String getWord() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter a word: ");
        String word = "";
        word = scanner.nextLine();
        try {
            checkWord(word);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
        return word;
    }

    public static void writFile(String[] words, String fileName) {
        try {
            FileWriter writer = new FileWriter(new File(fileName));
            for (String word : words) {
                writer.write(word + "\r\n");
            }
            writer.flush();
            writer.close();
        } catch (IOException e) {
            System.out.println("Error: Unable open/write file: " + fileName);
        }
    }

    public static ArrayList<String> readFile(String fileName) {
        ArrayList<String> words = new ArrayList<>();
        try {
            Scanner fileReader = new Scanner(new File(fileName));
            while (fileReader.hasNextLine()) words.add(fileReader.nextLine());
      } catch (FileNotFoundException e) {
            System.out.println("Error: Unable to read/open file: " + fileName);
        }
        return words;
    }


    public static void main(String[] args) {

        String word = getWord();
        System.out.println("You entered: " + word);
        String[] testData = {"January", "February", "March"};
        String fileName = "data.txt";
        writFile(testData, fileName);
        ArrayList<String> fileContents = readFile(fileName);
        System.out.println("File Contents:");
        for (String content : fileContents) {
            System.out.println(content);
        }

    }
}

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