Java Program to Make a File Read-Only

Read-Only is the file attribute that the operating system assigns to the file. When the file is flagged as read-only, it means that it can only be opened or read, one cannot change the name of the file, can not rewrite or append the content of the file, and also cannot delete the file.

Method 1:

Using setLastModified Method

To make the file read-only, setReadOnly() method of File Class is used. This method returns the boolean value, which is used to check whether the task(to make the file read-only) got successful or not. If the value returned by the method is true, it means that the task was successful and vice versa.

Parameters: The function doesn’t require any parameters.

Return Value: The function returns boolean data type. The function returns true if the File object could be set as Read-Only else false.

Exception: This method throws SecurityException if the method does not allow to write access to the file

Java

// Java program to make the file as read only

import java.io.File;

public class GFG {

    public static void main(String[] args)
    {
        // flag variable which contains the boolean
        // value returned by setReadOnly() function
        boolean flag;

        try {

            File file = new File("/home/mayur/GFG.java");

            // creates a new file
            file.createNewFile();

            // flag the file to be read-only
            flag = file.setReadOnly();

            System.out.println("Is File is read-only ? : "
                               + flag);

            // checking whether Is file  writable
            flag = file.canWrite();
            System.out.println("Is File is writable ? : "
                               + flag);
        }

        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Output:

Method 2: Using setWritable() method

Here by passing “false” as an argument to the setWritable() method, we can make a file read only.

The following code will help you understand how to make a file read only using setWritable().

Java

import java.io.File;

public class ChangetoReadOnly {

    public static void main(String[] args)
    {
        try {
            File file = new File(
                "C://Users//sai mohan pulamolu//Desktop//test.txt");

            // making the file to read only mode
            file.setWritable(false);

            // check if the  file is writable or not
            // if not writable then it is readonly file.
            if (!file.canWrite()) {
                System.out.println(
                    "This File is read only.");
            }
            else {
                System.out.println(
                    "This File is writable.");
            }
        }
        catch (Exception e) {
            System.out.println(
                "Sorry unable to change to readonly mode.");
        }
    }
}

Output: