In this article, you'll learn how to make a file read-only using Java. To make a file read-only in Java, you can use the File.setReadOnly() method. Here is an example:

File file = new File("input.txt");

// make file read-only
file.setReadOnly();

// verify if file is made read-only
if (!file.canWrite()){
    System.out.println("File is read-only.");
} else{
    System.out.println("File is writable.");
}

Alternatively, you can use File.setWritable() method (Java 6+) to mark any file read-only as shown below:

File file = new File("input.txt");

// make file read-only
file.setWritable(false);

// verify if file is made read-only
if (!file.canWrite()){
    System.out.println("File is read-only.");
} else{
    System.out.println("File is writable.");
}

To make any read-only file writable, you can use the same File.canWrite() method:

File file = new File("input.txt");

// make file writable
file.setWritable(true);

Further Reading

You may be interested in other Java I/O articles:

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