Read Only file import java.io.*; public class ReadOnly { public static void main(String[] a) throws IOException { File f = new File("f"); if (!f.createNewFile()) { System.out.println("Can't create new file."); return; } if (!f.canWrite()) { System.out.println("Can't write new file!"); return; } if (!f.setReadOnly()) { System.out.println("Grrr! Can't set file read-only."); return; } if (f.canWrite()) { System.out.println("Most immutable, captain!"); System.out.println("But it still says canWrite() after setReadOnly"); return; } else { System.out.println("Logical, captain!"); System.out.println("canWrite() correctly returns false after setReadOnly"); } } }