To implement Java Program to perform file IO

Explanation

This Java program demonstrates the basics of File Input/Output (I/O) operations using character streams. Specifically, it shows how to write text data into a local text file named Written.txt using the FileWriter class.

Here is a step-by-step breakdown of how the code works:

1. Importing the Required Class: The program starts by importing java.io.FileWriter. This class is part of Java’s standard I/O package and is specifically designed for writing character files.

2. Main Method and Exception Handling: The main method is declared with throws Exception. Since file operations are prone to runtime errors (like permission issues or disk-full errors), Java requires these operations to handle or declare potential IOExceptions.

3. Defining the Data: A String variable str is initialized with the text content: "File handling in java using FileWriter and FileReader".

4. Opening the File: The line FileWriter fw = new FileWriter("Written.txt"); instantiates a FileWriter object. This action attempts to open a file named Written.txt in the program's local directory. If the file does not exist, Java automatically creates it. If it already exists, its contents will be overwritten by default.

5. Writing Character-by-Character: The program uses a for loop to iterate through each character of the string str.

   • str.length() determines how many characters are in the string.
   • str.charAt(i) extracts the character at the current index i.
   • fw.write(...) writes that single character into the file stream.

6. User Feedback: Once the loop finishes writing all characters, System.out.println("Writing successful"); prints a confirmation message to the console.

7. Closing the Stream: Finally, fw.close(); is called. Closing the stream is a critical step because it flushes any buffered data directly into the physical file and releases system resources associated with the file.

Algorithm

1. Start the program.
2. Define the string literal str containing the text to be written.
3. Create an instance of FileWriter by passing the target file name "Written.txt" as a parameter.
4. Initialize a loop counter i = 0 to run until i is less than the length of the string.
5. Extract the character at index i using str.charAt(i) and write it to the file using fw.write().
6. Increment the loop counter i by 1 and repeat steps 5–6 until the end of the string is reached.
7. Print "Writing successful" to the console to indicate the process is complete.
8. Close the FileWriter object to flush the buffer and release the file lock.
9. End the program.