Java — Create Read only file or Mark a file as Read only | Code Factory

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You’ll learn how to create a read only file or mark an existing file as read only.

Java create Read only file

The following example demonstrates how to create a read-only file using the createFile() method of java.nio.file.Files class.

Posiz is not working on Windows.

package com.example.java.programming.file;
import java.io.IOException;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.Set;
/**
 * @author code.factory
 *
 */
public class CreateReadOnlyFileExample {
	public static void main(String... args) {
		try {
			// File Path
			Path filePath = Paths.get("test.txt");
			// File permissions (Read only for USER, GROUP, and OTHER)
			Set<PosixFilePermission> permissions = PosixFilePermissions.fromString("r--r--r--");
			FileAttribute<Set<PosixFilePermission>> fileAttributes = PosixFilePermissions.asFileAttribute(permissions);
			// Create a file at the given file path with the given attributes
			Files.createFile(filePath, fileAttributes);
			System.out.println("Read only file created successfully");
		} catch (FileAlreadyExistsException e) {
			System.out.println("File already exists");
		} catch (IOException e) {
			System.out.println("An I/O error occurred: " + e.getMessage());
		} catch (SecurityException e) {
			System.out.println("No permission to create file: " + e.getMessage());
		}
	}
}

Create a Read only file or Mark a file as Read only

There is another way to create a read only file or mark an existing file as read only using the java.io.File class’s setReadOnly() or setWritable() methods. The following example demonstrates the usage.

Note: you should try to use the previous method because that’s extensible and gives you more control.

Below code will work on Windows.

package com.example.java.programming.file;
import java.io.File;
import java.io.IOException;
/**
 * @author code.factory
 *
 */
public class CreateReadOnlyFileExample {
	public static void main(String... args) {
		try {
			// File Path
			File file = new File("test.txt");
			boolean isCreated = file.createNewFile();
			if (isCreated) {
				System.out.println("File created successfully");
				boolean success = file.setReadOnly(); // or file.setWritable(false);
				if (success) {
					System.out.println("File marked as read only");
				} else {
					System.out.println("File could not be marked as read only");
				}
			} else {
				System.out.println("File already exists");
			}
		} catch (IOException e) {
			System.out.println("An I/O error occurred: " + e.getMessage());
		} catch (SecurityException e) {
			System.out.println("No permission to create file: " + e.getMessage());
		}
	}
}