How to overwrite a file in Java

Can we overwrite a file using Java? Yes! In this blog, you will learn how to overwrite a file in Java using java.io.FileWriter class.

Class FileWriter

This class belongs to java.io package this class is used to write a character into the file. We can create or overwrite a file using java.io.FileWriter class.

Declaration

public class FileWriter extends OutputStreamWriter

Constructors

FileWriter(File file)
FileWriter(File file, boolean append)
FileWriter(FileDescriptor fd)
FileWriter(String fileName)
FileWriter(String fileName, boolean append)

Code with explanation for overwriting a file in Java

Here we overwrite a .txt file using java.io.FileWriter class.

import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class OverwriteFile {

    public static void main(String[] args) {
        Scanner scObj = new Scanner(System.in);
        System.out.println("Input the contents of the file."
                + "\n===================================");
        
        String content = scObj.nextLine();
        scObj.close();
        try {
            FileWriter writerObj = new FileWriter("F:\\WorkFile.txt", false);
            writerObj.write(content);
            writerObj.close();

            System.out.println("================================\n"
                    + "File successfully overwritten.");
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

Output
Input the contents of the file.
===================================
hello, you are viewing a java blog on codespeedy website
================================
File successfully overwritten.

Also, you can see Workfile.txt

Explanation

Line 8 – 12: In this code, we created an object named scObj of Scanner class to read input and store in the String content variable using scObj.nextLine() method.
Line 14 – 16: Here in try block we created an object named writerObj of FileWriter class and also we pass the File Location value in a string and a false Boolean value in the FileWriter parameter constructor. Now using writerObj.write(content) we write the string data in the WorkFile.txt.
The reason why we pass the false boolean value? If you want to overwrite a file, you must pass the false boolean value and to append in file, you must pass the true boolean value in the parameter of FileWriter() class.
Line 21 – 23: Here we catch the exception which may be thrown by FileWriter class.

Also read: Reading and writing a file in java using FileWriter and FileReader

That’s enough for a how to overwrite a file in Java.

Thank you