This is a very minor bug. If a file isn't writeable and a program
attempts to write to it, the exception thrown is java.io.FileNotFoundException.
This is a bit confusing, since the file does exist. Suppose the file
/home/mrm/notwriteable exists but has write permissions turned off.
The following program demonstrates the bug. Thanks to Charlie Lai for
figuring this out.

import java.io.*;
 
public class WriteFile {
    public static void main(String args[]) {
        try {
            PrintWriter out = new PrintWriter
                        (new BufferedWriter
                        (new FileWriter("/home/mrm/notwriteable")));
            out.println("hi there");
            out.flush();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}